"What's your favorite stock?" Many investors, when asked a quick off-the-cuff question like that, may gravitate toward familiar names such as Apple (AAPL) or Facebook (FB). And well they should. Yes, these have been two of the market's best stocks for some time, but they've been so successful for a reason. In both cases, like many other high-profile names, the companies have proven they can sell a product or service.

However, not every great investment is a monster-sized company or a headline-grabbing outfit. Sometimes, an organization that's a bit off the beaten path can bear quite a bit of fruit. It pays to invest in the big boys, but off-the-radar businesses are worth a look, too.

Here's a review of 20 tickers across numerous industries that investors of all stripes should explore. They're not household names, but that doesn't mean they aren't doing well, or that they can't be among the market's best stocks going forward.

Indeed, their obscurity is part of what makes them so compelling.

Align Technology

Industry: Dental products

Market value: $20.9 billion

Most people remember Nvidia (NVDA) and Boeing (BA) as Standard & Poor's 500-stock index components that had breakthrough performances in 2017. But many people don't realize that Align Technology (ALGN, $262.00) did even better, gaining 131% to finish second in the index behind only NRG Energy (NRG), by about one percentage point.

You know the company, even if you think you don't. Align Technology is the name behind Invisalign dental braces, which straighten your teeth without using uncomfortable and unsightly metal wiring.

Wall Street's pros believe Align's top line grew 34% in 2017, which should be enough to power a 50% year-over-year improvement in per-share profits. Analysts expect more of the same this year.

While 2018's growth outlook is impressive, ALGN shares aren't exactly cheap. The stock trades at 89.6 times trailing earnings and 45 times analyst projections for next year's profits - and at the same time rivals such as Candid and Smile Direct Club are turning up the heat. This suggests Align shares could be due for some profit-taking. But any dip may be an entry opportunity, because the company knows exactly where it fits into the picture.

"As we transform the dental industry from using old analog approach to straightening teeth with metal braces, to using digital technology," Sreelakshmi Kolli, Align's vice president of information technology, recently explained. "I am constantly thinking about how we stay ahead with the right team capabilities, business processes and technologies to remove barriers to adoption."

Arconic

Industry: Metals products

Market value: $14.4 billion

Arconic (ARNC, $30.06) is a name that you might be more familiar with had the company that spun it off done a better job of publicizing the split and explaining the rationale better. See, Arconic is the former specialty materials arm of Alcoa (AA), which separated from the bigger but struggling aluminum side of the organization in 2016. Some investors that only plug into the media's splashiest headlines haven't yet noticed, while others have largely forgotten it.

That's too bad. Materials such as titanium and specialty metals needed by the military and aerospace industries are good businesses. And both may boom soon, too, if Boeing's recent outlook is anywhere near being on target.

The aircraft maker thinks airlines will need to purchase more than 41,000 new aircraft over the course of the next 20 years, versus the 23,500 that are in use as of today. That's good news for Alcoa, but it's even better news for Arconic, as aircraft designs are less and less reliant on aluminum.

Corcept Therapeutics

Industry: Biotechnology

Market value: $2.9 billion

When traders take a wild swing on a small biotech stock, they hope for a story like the one that has taken shape around Corcept Therapeutics (CORT, $23.02) during the past few years.

As recently as 2012, Corcept had no revenue, and therefore no income. Indeed, it was booking losses, as it was paying for the development of a drug called Korlym for the treatment of Cushing's syndrome. Since its approval in late 2012, revenue has grown from nothing to Q3's top line of $42.8 million. That was up 97% year-over-year. Even more impressive is that the quarterly profit widened from 2 cents per share from a year earlier to 11 cents per share. Experts expect similar growth in the foreseeable future.

So far, Corcept is a one-trick pony; Korlym is its only product. But unlike so many of its biotech peers, that one product is driving some incredible, profitable growth. Even more shocking is that the stock's forward-looking P/E is a palatable 27.6.

DXC Technology

Industry: Information technology services

Market value: $28.4 billion

DXC Technology (DXC, $99.55) is a $28 billion behemoth that most people couldn't tell you the first thing about. In fact, some people who know exactly what DXC is still may have a tough time explaining it.

In layman's terms, DXC Technology is a global IT services outfit that delivers a wide range of solutions to all sorts of technical problems. It's off the radar because it's young, though its roots are in much more familiar businesses. The company was formed in early 2017 via the merging of CSC and the Enterprise Services Division of Hewlett-Packard Enterprise (HPE). Investors - as well as many would-be clients - still are trying to make the connection.

DXC Technology has made the connections it needs to, though, putting its finger on the pulse of the IT market and how it's changing. As Chief Technology Officer Dan Hushon wisely observed in the company's 2018 IT outlook, "Forced to rethink big data, companies will use advanced machine learning techniques to make better decisions with less data." It was a gutsy but insightful assessment.

That's a big reason why analysts are forecasting earnings growth of 16% next year, up from this year's projected profit of $7.54 per share.

EcoLab

Industry: Diversified industrials and chemicals

Market value: $39.8 billion

Here's a mind-blowing stat: The average person in the United States uses between 80 and 100 gallons of clean water every day.

That wasn't a problem until recently. The world had plenty of potable water, and when it wasn't readily available, it could be scrubbed from some nearby source. But between population growth and the creation of more and more pollutants, clean water isn't nearly as cheap or easy to come by as it used to be. Just look at Cape Town, South Africa, which is projected to run out of fresh water by mid-April of this year.

That's where an outfit called EcoLab (ECL, $137.68) comes into the picture. EcoLab provides solutions that not only help individuals, institutions and local governments better handle their thinning supply of water, but also avoid wasting water in the first place. For instance, its Kay QSR Machine Warewashing system can reduce the use of water by as much as 75%.

EcoLab does more than water management, but that's a large and vital piece of its business. And given that the need for clean drinking water keeps growing, you'll likely hear more about this company (and stock) in the future as it grows its top and bottom lines.

First Data

Industry: Payments technology

Market value: $14.4 billion

When most investors think of commerce middlemen, names such as Visa (V) or MasterCard (MA) comes to mind. As the biggest credit card names in the world, the pair of powerhouses are everywhere.

But don't think MasterCard and Visa are one-stop solutions for retailers and other businesses. Any organization that accepts payments from customers needs the right hardware to make that happen; most of them would also like a means of creating and managing a customer database. Shoppers also still write checks.

Enter First Data (FDC, $17.70), which offers solutions to all of those challenges, and more. Thus, it's very likely you've used your Visa or MasterCard at a shop utilizing First Data's equipment without even realizing it was the provider of the modern-day cash register.

This isn't a high-growth business, but it's a reliable one in terms of revenue and profits. And with consumer confidence reaching multiyear highs in November, an unemployment rate at multiyear lows and an economy that finally looks like it's reached escape velocity, FDC may well be on the cusp of accelerated earnings growth.

Fluor

Industry: Engineering and construction

Market value: $8.5 billion

Everything Fluor (FLR, $60.70) does is something the average investor likely doesn't entirely understand. The company brings technical solutions to the energy, mining, construction, healthcare and infrastructure markets - goods and services most people never think about, or get excited about.

But 2018 could be an exciting year for FLR shareholders.

That's the way Baird analyst Andrew Wittmann sees it. He recently upgraded Fluor on what he sees as a turning point for the engineering and construction industry. He wrote, "E&C industry fundamentals offer some of their better growth prospects in years with nearly all major end-market verticals participating." Wittmann's thoughts underscore data from the Bureau of Labor Statistics released earlier this month, which indicated the construction industry hired 30,000 workers in December to add a net 210,000 jobs for the full year. The hiring spree points to optimism from builders about the coming year.

Wittmann also pointed out that, despite a disappointing 2017, Fluor's balance sheet could help the stock stave off any further downside.

Gardner Denver Holdings

Industry: Industrial equipment

Market value: $6.8 billion

Industrial outfit Gardner Denver Holdings (GDI, $34.58) may be one of the market's best-kept secrets.

The company makes industrial fans, blowers and compressors. It's not a bad business to be in, particularly with the United States at the precipice of strong economic growth, led by a revival of the nation's manufacturing industries. In fact, manufacturing is expected to grow faster than the overall economy through 2020, potentially ramping up the need for more and better industrial equipment.

The undertow is enough to prompt analyst earnings expectations of $1.62 per share this year for Gardner, up from 2017's projected bottom line of $1.30 per share.

Why haven't you heard about this nearly $7 billion company? Part of the disinterest stems from the fact that pumps and blowers don't exactly make for scintillating headlines. The other part of its obscurity, however, lies in its lack of history as a standalone outfit. It had been a privately held company until May of last year, when it unceremoniously rejoined the public markets.

Just don't let the lack of headlines fool you.

II-VI

Industry: Scientific materials and devices

Market value: $2.7 billion

II-VI (IIVI, $42.65) didn't do itself any favors in the "memorable company name" department. In fact, the name itself is designed to be a puzzle. Still, to the right electrical engineer, II-VI wins points for being clever.

Straight from the company's website: "The Roman numerals 'II-VI' refers to group II and group VI of the Periodic Table of Elements. By chemically combining elements from these groups, II-VI produced the infrared optical crystalline compounds: Cadmium Telluride (CdTe), Zinc Selenide (ZnSe), Zinc Sulfide (ZnS) and Zinc Sulfide MultiSpectral (ZnS MS). These compounds and others created from group II and group VI elements are commonly referred to as 'II-VI Materials.'"

These elements are suited for making a variety of engineered materials and optoelectronic components. In layman's terms, II-VI makes things like lasers, fiberoptic hardware, semiconductor equipment and crystals for use in a variety of industries.

It's boring to the bone, but the double-digit growth in the top and bottom lines that II-VI has mustered for several years makes it not nearly as yawn-worthy.

Lamb Weston

Industry: Potato products

Market value: $8.5 billion

Most investors probably haven't heard of Lamb Weston (LW, $58.60), but they've probably heard of its most cherished customer. Lamb Weston supplies the sliced and frozen potatoes that eventually become the French fries sold by the world's biggest fast food chain, McDonald's (MCD).

McDonald's is hardly the only customer Lamb Weston serves, however. The restaurateur only accounts for 11% of Lamb Weston's business, so the company still offers plenty of diversity among its revenue spigots.

Lamb Weston is mired in obscurity in part because it's a relatively new entry. The company was spun off from ConAgra (CAG) in late 2016 in a fairly low-key fashion. It's doing fine all the same, though. Per-share profits are expected to roll in at $2.46 for 2017 - up from $2.32 in 2016 - and then move on to $2.87 this year.

As long as people continue to enjoy (and need) fast food, Lamb Weston will have a market.

Mercadolibre

Industry: Internet retail

Market value: $17.1 billion

Mercadolibre (MELI, $387.10) is essentially Latin America's version of eBay (EBAY). The company operates an online auction site catering to South American and Central American shoppers, and is expected to generate $1.4 billion worth of revenue in 2017 within its mostly underserved emerging markets. That top line, once the results for the last quarter of the year are tallied, should be up more than 60% from 2016's sales.

But the most exciting aspect of the largely untold Mercadolibre story is that MELI shares more than doubled last year.

Not every analyst is looking for another wave of bullishness in 2018. Citi analyst Paola Mello downgraded Mercadolibre late last year, lowering Citi's official target price on the stock to $230 - more than 30% below its current value. Who can really blame Mello? With trailing and forward P/E ratios both around 125, the stock is anything but affordably priced.

But this company has proven very successful, and the pros are collectively calling for another round of strong double-digit sales growth this year. That could keep the valuation boogeyman at bay.

MKS Instruments

Industry: Scientific materials and devices

Market value: $5.8 billion

Previously mentioned II-VI isn't the only unknown company helping to build the world's techno-electrical backbone that's worth a look. There's an outfit called MKS Instruments (MKSI, $102.30) that's just as obscure yet just as noteworthy.

MKS Instruments brings numerous products to the table, including gas-flow delivery solutions, opto-mechanics, vacuums, automation, microwaves and more. Few people understand what it makes and markets, and even fewer people would care. But everyone would notice if MKS and its peers suddenly decided to stop supplying the world's manufacturers and factories.

For the record, only seven analysts follow MKSI. However, four call it a strong buy, collectively saying it's worth $117.83 per share. That's roughly 15% better than its current price.

Momo

Industry: Social media

Market value: $6.2 billion

Talk about a killer year. Once the final tally is taken, Chinese internet sensation Momo (MOMO, $31.53) is expected to have more than doubled its revenue from 2016 to 2017, and almost have doubled its earnings.

Momo is a social networking and "meet up" platform unlike any other. Rather than connecting you online with friends you already know regardless of their location, Momo points out other nearby Momo users. The app also informs you about nearby events, puts you in touch with groups of like-minded individuals and more. It's as much about making friends as it is keeping in touch with them.

The last few months haven't been great for Momo shareholders, with the stock peeling back 30% from its mid-2017 peak. A handful of analysts have dropped coverage, too, which has been viewed more of a negative than a neutral.

But nothing has actually stopped the company's forward operational progress.

ServiceNow

Industry: Enterprise software-as-a-service provider

Market value: $26.6 billion

ServiceNow (NOW, $148.87) is one of those IT consulting companies that few people realize are hard at work. If you've bought anything from Overstock.com (OSTK), Tempur-Sealy (TPX) or Lexmark (LXK), however, you've somehow benefited from ServiceNow's experience and expertise.

The simplest explanation is, ServiceNow makes technology work for organizations that need their technology to do more work. Automation, analytics and app-building are just a few of the things it has done for numerous entities.

The proof of its value is in its growth. Revenue was on pace to improve 38% in 2017, and analysts are calling for 30% sales growth this year. That's enough momentum to push profits up from 70 cents per share in 2016 to $1.19 for 2017 to a projected bottom line of $1.81 this year.

Take-Two Interactive

Industry: Video games

Market value: $14.5 billion

Take-Two Interactive (TTWO, $126.67) relatively small compared to rivals Activision-Blizzard (ATVI) and Electronic Arts (EA). And outside of the world of video gaming, Take-Two doesn't even always ring a bell.

But that's largely by design. Take-Two has focused on game quality rather than quantity, which necessitates keeping the operation small rather than letting it become bloated. BMO Capital Markets analyst Gerrick Johnson explained it best a couple months ago, when he wrote:

"The knock against the company had always been that it was overly reliant on just a few games ... creating a lumpy, unpredictable, and risky earnings stream. But in the digital era this is a competitive advantage. By having some of the highest-quality games ... Take-Two can keep its players engaged and spending in its games without having to reinvent the wheel every 3-5 years. The company's earnings stream is now predictable, reliable."

The formula works. The pros expect Take-Two's bottom line to grow nearly 6% this year but 44% next year on heels of the next installment of the Grand Theft Auto series, its Red Dead Redemption franchise and a whole slew of popular titles from its 2K Games arm.

The shift toward game downloads and away from disc-based or cartridge-based games also plays into Take-Two's strengths. Piper Jaffray analyst Michael Olson recently told clients, "We remain positive on the group and believe digital revenue growth, both add-on content and full-game downloads, can provide an underlying tailwind through 2018. In particular, we expect to see accelerating momentum around the mix shift toward full-game downloads."

Tower Semiconductor

Industry: Semiconductors

Market value: $3.4 billion

When investors think of semiconductor stocks, icons like Intel (INTC) and Qualcomm (QCOM) come to mind. That makes sense. After all, they're the biggest, and their hardware is found more often in more devices than most other makers.

Qualcomm and Intel aren't the only outfits making chips, though. Tower Semiconductor (TSEM, $34.74) is in the mix as well, even if it's only a fraction of the size of its bigger brothers.

That smaller size hasn't held Tower back, mind you. The company, also known as TowerJazz, is a foundry specialist that offers development and production solutions to better-known semiconductor manufacturers. Revenue is likely to roll in 11% higher for 2017, driving a 25% improvement in per-share profits.

Where Tower really shines, however, is return on equity. The company sports a trailing ROE of 27%, which is more than twice the industry's average. Investors just aren't noticing. Yet.

Tucows

Industry: Internet services

Market value: $570 million

You likely have used a Tucows (TCX, $54.20) service and not even realized it. Tucows operates website domain-management platforms Hover, Enom and OpenSRS. It's the name behind mobile telecom service Ting Mobile and high-speed internet service Ting Fiber. You also may know it as an online repository of all sorts of software (some free, some not) under the Tucows name.

This company is experiencing the most growth because it's making headway with Ting. Both the internet and mobile markets are saturated, but when you're starting with nothing (as Tucows was just a few years ago), even a small piece of either market makes a big difference. To put it in numerical terms, last quarter's revenue of $85 million was up 73% year-over-year. An acquisition helped, but even without that deal, Ting's organic growth was 13%.

Tucows isn't wildly profitable, but investors still have liked the company's progress enough to bid it up 170% in two years. A recent dip in TCX, meanwhile, has brought its forward price-to-earnings estimate to a reasonable 19.

Universal Display

Industry: Lighting technology

Market value: $7.3 billion

Don't let the generic-sounding name fool you. Universal Display (OLED, $159.40) is a standout company, and the "OLED" ticker is an acronym for what Universal Display makes - a product that is about to become the norm in all technologies with a visual interface.

OLED is short for "organic light-emitting diode." This is the next generation of display screen technologies, poised to follow the LED, LCD or maybe plasma screen you're using right now. The organic version of LEDs offer not just better power efficiency, but a more vivid image, too.

These screens aren't exactly new. Samsung has used OLED screens in its Galaxy devices for several years now, and you can find them in a few nicer television sets. But it's Apple that should start the OLED race in earnest, as it used an OLED screen for the first time in its iPhone X.

Other companies make OLED screens, but none of the others are as tightly focused as Universal Display is.

Weibo

Industry: Social media

Market value: $28.9 billion

Weibo (WB, $129.57) often is referred to as the Twitter (TWTR) of China, but it's a comparison that doesn't do the social networking platform justice. Unlike Twitter in the western part of the world, Weibo has been quite successful - and profitable - because it's also quite like Facebook, blending the best of both destinations in a market that works to exclude U.S.-based competitors.

Weibo hasn't gone entirely overlooked. A handful of analysts in the United States have taken notice. UBS analyst Jerry Liu is one of them. He wrote earlier this month, "Weibo has established itself as a unique and sustainable social network, and we expect long-term growth in number of users and better monetization. We see Weibo as Twitter but, importantly, with Instagram-like features."

Liu certainly has to be eyeing the fact that Weibo's top line grew 81% last quarter on a year-over-year basis, prompted by a 26% increase in the number of monthly users that are increasingly logging in on mobile devices.

WestRock

Industry: Packaging manufacturing

Market value: $16.9 billion

What's something you likely handle several times a day, is absolutely required for almost all commerce, yet you rarely think twice about? Boxes, packaging and bags. We all consume several ounces (if not pounds) of it every day, with most of it left in recycling bins to start the cycle all over again. Try to function one day without some sort of packaging, and you'll be surprised how quickly consumer-facing product sales would simply shut down.

It's a scenario that plays right into WestRock's (WRK, $66.63) hand. WestRock provides the cardboard and paper that gets turned into the boxes and bags you rely on.

Boring? You bet. That's the point. But this isn't boring: The corrugated box packaging market is expected to grow at an annual pace of 4.8% through 2020. With WestRock riding that wave, analysts believe the company will grow earnings by almost 50% this year.

You can thank Amazon.com (AMZN) and its rivals for the advent of the online-shopping mania that has made deliveries preferable rather than taking a trip to the mall.

James Brumley is a contributing writer at Kiplinger.