It's hard to believe, but 2019 is halfway over. Even though the first half of the year has been turbulent at times, the trade war persists, there's lots of uncertainty surrounding what the Federal Reserve will do next, and tensions with Iran are heating up, the stock market is knocking on the door of new record highs.

Despite the overall high stock prices, there are still some attractive opportunities to be found. We asked five of our top contributors what stocks look most interesting to them, and here's why they think PayPal (NASDAQ:PYPL), Shopify (NYSE:SHOP), iRobot (NASDAQ:IRBT), Store Capital (NYSE:STOR), and Pattern Energy Group (NASDAQ:PEGI) look especially appealing.

Sandy beach with palm trees

The weather is hot, and so is the stock market. Here are some stocks that could still be good deals. Image source: Getty Images.

Just scratching the surface of its potential

Matt Frankel, CFP (PayPal): One stock that popped onto my radar recently is payments giant PayPal, which has had a tremendous year so far. The stock is up by about 35% so far in 2019, but it recently pulled back after it was announced that COO Bill Ready plans to leave the company at the end of this year.

To be fair, it's understandable that the market wouldn't be thrilled about this news. After all, Ready had been expected to play a key role in the monetization of the ultra-popular Venmo platform going forward. Ready had also been a driving force behind PayPal's strategic move to turn the company's largest competitors, such as Visa, Mastercard, Apple, and others, into partners.

However, keep in mind that Ready is staying on for another six months in order to ensure a smooth transition of leadership. Plus, it's important not to lose sight of PayPal's long-term potential, no matter who is in charge. After all, Venmo's total payment volume grew at a staggering 73% year-over-year pace in the first quarter, and even PayPal's core merchant services payment volume continues to grow rapidly, with a 29% rise.

PayPal continues to add new users to its platform, despite its already massive size. During the first quarter alone, the company added 9.3 million new active users and processed $161 billion in payments -- that's an annualized pace of more than $640 billion. New partnerships with Instagram, MercadoLibre, and others have the potential to fuel even more growth.

Still, Venmo remains the company's most promising long-term profit engine. The wildly popular payment platform has more than 40 million active accounts and is processing payment volume at an annualized rate of more than $84 billion -- and growing fast. And, Venmo has been integrated into several popular platforms, such as Uber, Grubhub, Fandango, Hulu, and more. In short, as Venmo becomes more and more useful on a daily basis for consumers, adoption will continue to increase, and payment volumes will continue to rise -- after all, while 40 million users is certainly impressive, Venmo's current user base represents only about 15% of the adult population of the United States.

And Venmo is still in the early stages of monetization. Things like the Venmo debit card, Instant Transfer, and Pay with Venmo helped increased the platform's annualized revenue run rate by 50% to $300 million over the first three months of 2019 alone. Even so, this is a drop in the bucket when you consider that PayPal expects about $18 billion in revenue this year. However, as Ready said during the company's first-quarter earnings call, Venmo users are "deepening their engagement with us and are looking for more and more products from us." So, the potential to multiply the revenue run rate several times over is certainly there.

In short, PayPal is growing tremendously, and if the company is able to successfully monetize its Venmo platform, there could be tremendous upside ahead.

Don't miss this e-commerce play

Chris Neiger (Shopify): If you haven't heard of Shopify, now is an excellent time for a proper introduction to this growing e-commerce opportunity. The company's cloud-based platform allows businesses of all sizes to easily set up their own online stores and begin selling their products and services.

Why should investors care about Shopify's e-commerce platform? Because the company is helping businesses transition to the fast-growing e-commerce market that's expected to be worth $24 trillion by 2025. E-commerce sales will account for just 11% of all retail sales in the U.S. year, which means there's still plenty of room for Shopify to help bring more merchants online.

Fortunately for Shopify (and its investors), the company has already been very successful at tapping into this e-commerce opportunity. Shopify has grown the number of merchants who use its platform from 500,000 to more than 800,000 in less than two years. And with that rapid growth has come impressive sales. In the most recent quarter, Shopify's revenue grew 50% year over year to $320.5 million, and its adjusted net income topped $10 million, up from $4.2 million in the year-ago quarter.

Shopify's sales come from the company's two revenue segments: subscription solutions and merchant solutions, both of which are performing well. The subscription solutions segment includes sales generated from subscriptions to the company's platform, along with add-on items like website themes and domain sales. In the first quarter of this year, subscription solutions sales popped 40% year over year and accounted for 44% of the company's top line.

Shopify's merchant solutions business, which is primarily driven by charging payment processing fees to merchants, is also on the rise and jumped 58% from the year-ago quarter to $180 million.

Additionally, Shopify is experiencing strong growth from the company's Shopify Plus service, which is a platform for its enterprise customers. Shopify Plus now accounts for 26% of the company's monthly recurring revenue, and Shopify just redesigned the service to make it even more useful to its clients than ever before.

If all of that weren't enough, Shopify recently said that it's launching a new fulfillment service with a "dedicated network of fulfillment centers that will ensure timely deliveries, and lower shipping costs" for its customers. This is a big move for Shopify, one that the company is investing $1 billion to make, and it will help it better compete with Amazon as it attempts to lure more businesses to its platform.

Investors looking to tap into the growing e-commerce market should give Shopify's shares strong consideration. The company is quickly growing its sales, it has tons of room to tap further into the U.S. e-commerce market, and its recent move into fulfillment could make it a compelling alternative to Amazon for many businesses.

This pullback might not last long

Steve Symington (iRobot): Down more than 30% since the day before its first-quarter 2019 report in late April, it seems an understatement to say shares of iRobot have been taken to the cleaners over the past two months. 

The thing is, while iRobot's quarterly revenue (up 9.5% to $237.7 million) technically arrived below Wall Street's expectations (for $251 million), CFO Alison Dean insisted during the subsequent conference call that sales were in line with iRobot's internal targets. To that end, iRobot reaffirmed its full-year guidance for revenue to increase 17% to 20% year over year, or to a range of $1.28 billion to $1.31 billion, and for operating income in the range of $108 million to $118 million. 

That raises the question: Given its surprisingly soft start, how will iRobot close the gap over the rest of the year? In the near term, company chairman and CEO Colin Angle is counting on a combination of continued "strong global demand" for iRobot's current products, followed by an acceleration brought on by the recent launch of two new products. The latter includes its vastly more powerful Roomba s9+ robotic vacuum and Braava jet m6 floor-mopping robots, which can actually work together using a new "Linked clean" process to tag-team your cleaning duties.

Later this year, iRobot will also launch its new Terra robotic lawn mower -- first in Germany and as a beta program in the United States -- which should effectively open the (patio) doors to a new multibillion-dollar market. That's also not to mention the fruits of iRobot's recent partnership to advance smart-home technologies with Alphabet subsidiary Google, which I've argued could be the impetus for an acquisition down the road. And over the longer term, iRobot has expressed interest in creating niche robotics solutions to tackle tasks like bathroom cleaning and laundry folding.

But I'd be remiss if I didn't offer a few notes of caution.

First, the Roomba s9+ and Braava jet m6 are expensive, retailing for a whopping $1,300 (with the S9+ automatic dirt disposal system) and $500, respectively, and the Terra will almost certainly cost even more. Though the company has carved out an enviable position catering to robotics consumers who haven't been particularly sensitive to its premium price points over the years, its latest lineup will definitely put that position to the test.

Relatedly, by diversifying its supply chain and selectively raising prices, iRobot has been successful so far in offsetting the incremental cost of tariffs on products manufactured in China and imported to the United States. But if the U.S.-China trade war escalates further, it could severely hamper iRobot's ability -- at least in the short term -- to extend that success. 

Here again, however, I think much of that risk has already been priced into iRobot's stock price today. For patient, long-term shareholders willing to buy now and hold iRobot as it dominates the nascent home-robotics industry in the coming years, I believe the pullback is an excellent opportunity to open or add to a position.

The prospect of lower interest rates supports this dividend play

Todd Campbell (STORE Capital): The Federal Reserve signaled in June that the next move in interest rates is more likely to be lower rather than higher. That's great news for real estate investment trusts, or REITs, because they rely heavily on debt to finance real estate purchases and a stable economy to maintain high occupancy rates.

There's no guarantee the Fed will cut the Fed funds rate, but its latest stance suggests higher borrowing costs aren't a threat anymore to STORE Capital, a REIT specializing in free-standing retail real estate.

Brick-and-mortar retail has struggled to shrug off declining sales due to e-commerce, but most of the industry's pain has been felt by mall operators, not owners of freestanding buildings like STORE Capital. Furthermore, unlike mall REITs, Store Capital's tenants are mostly service-oriented businesses, such as movie theaters, or businesses that are less at risk of disruption by Internet sales, such as furniture stores. This focus helps insulate it against the risk of store closures due to increasing online shopping trends.

Serving tenants resistant to e-commerce isn't STORE Capital's only edge, either. It also builds in protection from single-store failures by requiring unit level financial reporting from tenants on 98% of its 2,500 properties. This insight is another reason its occupancy rate was 99.7% in the first quarter.

The company also benefits from buying properties below their replacement cost, providing it with greater financial flexibility. For instance, it spent $400 million on new properties in Q1, and the average purchase was made at roughly 71% of its replacement cost.

Spending on new properties is a big reason STORE Capital's interest expense increased to $38.1 million from $29.3 million in the past year, but some of the increase was also due to average interest rates edging up five basis points. If interest rates fall, the company may be able to refinance existing debt and take on new debt at more favorable rates, providing a tailwind to its funds from operations (FFO), a measure that indicates how much money is available for shareholder-friendly dividends.

Since STORE Capital has already demonstrated it can grow FFO in a rising rate environment, it should be good news for investors if rates drop. For perspective, the combination of more properties and 2% annual rent increases on existing properties helped its adjusted-FFO increase 26% to $108 million in the first quarter. It currently pays a quarterly dividend of $0.33 per share, up from $0.31 per quarter last year, but it wouldn't surprise me if another dividend increase is coming because its dividend payout ratio is less than 70%. As of this writing, shares currently yield 3.79%.

High occupancy rates and its diligence in vetting tenants have made STORE Capital one of the most interesting REITs out there, a perception that's shared by one of the greatest investors of our time: Warren Buffett. Buffett's Berkshire Hathaway (NYSE: BRK-A)(NYSE: BRK-B) is STORE Capital's second largest shareholder, owning 18.6 million shares exiting Q1, worth $649 million as of June 25.

Since the fear of higher interest rates is fading, occupancy rates are high, and funds from operations are growing, investing alongside the Oracle of Omaha in this REIT is simply icing on the cake.

The winds have turned

Jason Hall (Pattern Energy Group): In late 2017 and through much of 2018, investors were understandably concerned about Pattern Energy. Without rehashing the details, the independent renewable energy producer, which had increased its dividend every quarter for the first 15 quarters after implementing it, froze the payout at $0.422 per share in early 2018, when its cash flow was at risk of being outpaced by its obligation to shareholders.

Things really came to a head in late 2017, however; the company's stock lost more than 30% of its value from September 2017 through March 2018, and it has bounced around a lot in the months since: 

PEGI Chart

PEGI data by YCharts.

In short, the market was coming to grips with the reality that Pattern spent essentially all of its cash flow in 2017 on dividends, and even after freezing the payout, it once again paid out nearly all of its cash flow in 2018. The big fear? The company was going to have to cut its payout, either because its lenders forced it to make a cut to access further capital to fund growth, or because credit markets simply tightened up, and it had no choice but to make a cut to free up cash. 

However, management has been steadfast that it had a plan to jump-start cash-flow growth and get to an 80% dividend payout ratio -- and that it would be able to maintain the current payout while that plan played out. In March, management laid out a two-year plan to grow cash flow by 20% by the end of 2020. So far this year, the company is exceeding expectations, having grown cash available for distribution 23% in the first quarter. 

That's far ahead of the roughly 5% CAFD growth the company says it would generate this year, and it indicates that management wasn't kidding around or exaggerating that it has both the opportunity and the wherewithal to deliver. 

One of the big advantages Pattern has in its corner is its relationship (and significant investment in) Pattern Development, the privately held project developer in which it has a nearly $200 million stake.

It gets two benefits from Pattern Development. First, it has right of first offer (ROFO) to acquire either a whole or partial stake in many of the renewable energy projects Pattern Development is heading up, putting it at the front of the line to pick and choose the best-returning of these assets to acquire. If it does acquire a project, it then profits from the long-term energy sales from that asset, typically under contracts that can exceed 20 years in length. 

Second, Pattern Energy will also start receiving distributions from Pattern Development in 2020 based on income the latter earns from projects it sells to other operators or investors. 

Put it all together, and there are so many things in Pattern Energy's favor. Its plan to grow cash flow is working. Its partnership with Pattern Development provides a strong pipeline of future growth, and it is set to also generate direct income from the development business.

That's a solid business with great prospects for many years of growth, and investors today can still capture a yield well above 7%. It may be 2021 before management is ready to increase the payout again, but I think once it gets back above that 80% CAFD payout ratio, Pattern Energy's future will be as one of the best dividend growth stocks to own over the next decade. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.