The stock market is trending upwards again, erasing the damage of a brutal 2022. The S&P 500 market index lost a dividend-adjusted 18% last year while the tech-heavy Nasdaq Composite showed a negative total return of 33%. As the inflation crisis lightens up and the usual Washington heavyweights are settling their debt ceiling differences, the Nasdaq has recorded a 25% rebound while the S&P 500 gained 10% year-to-date.

So things are looking up but the market still stands far below a full recovery. Here are two incredible growth stocks that still strike me as unfairly beaten-down buying opportunities right now. One is a trailblazer in the streaming media sector and the other has found a unique niche in the explosive e-commerce market.

Roku: The underestimated growth engine in media streaming

Let's start with the streaming technologist Roku (ROKU 2.55%).

It's not easy to pick long-term winners in the streaming video wars. Netflix (NFLX 1.84%) pulled that market up by the bootstraps and remains a global leader, but deep-pocketed giants Amazon.com (AMZN 2.94%) and Walt Disney (DIS 0.20%) are nipping at its heels in many markets. And pretty much every content studio runs an in-house streaming service of its own nowadays. The sector will surely consolidate in the end, boiling down to a smaller group of trend-setters and survivors. The exact list of big winners remains to be written, though the three streamers mentioned so far should have better odds than most upstarts and challengers.

Roku doesn't play that game. Sure, the company provides some ad-supported content on the Roku Channel, including top-notch original titles such as Weird: The Weird Al Story, but even that outlet is really just an advertising platform.

Zoom out to the bigger picture and you'll see that Roku sells the technical nuts and bolts that put the streaming content giants in your living room. So whoever walks away with the longest subscriber list in the end, Roku keeps winning as long as the digital media market keeps growing.

In every move that Netflix, Disney, or Amazon make to grow their global media sales, their efforts also support Roku's growth. 43% of smart TVs sold in the United States during last quarter were powered by Roku's media-streaming software. That's more than the next three alternatives combined.

That's the picture in the largest and most mature digital media market on the planet -- North America, including Canada and Mexico. At this point, Roku is pushing to build a dominant market position in places like the U.K., Germany, and Latin America. Broadcast and cable TV still monopolize the video-viewing experience in most countries but the long-term future will almost certainly be painted in pixels.

So Roku stares down an impressive runway to long-term sales growth, but skeptical market makers have tossed the stock in Wall Street's bargain bin anyway. A temporary slowdown in digital ad sales -- not just for Roku but across this sector as a whole -- has been interpreted as a long-term hardship. As a result, Roku shares are changing hands at just 2.5 times sales and 4.7 times cash on hand. That's comparable to traditional value stocks, not high-octane growth stories.

This stock looks spring-loaded to post a massive rebound when the global economy stabilizes, driving a worldwide return to generous ad spending.

Etsy: Handcrafted e-commerce growth

In the other corner, you'll find Etsy (ETSY 0.16%), an online marketplace for handmade, vintage, and rare items.

Like Roku, this stock has taken a beating in recent quarters. Also like Roku, Etsy's shares are trading at reasonable valuation ratios such as 4 times sales and 16.5 times free cash flow.

You know what else Etsy has in common with Roku? Both of these companies have carved out extremely specific and unique niches in their respective industries. And that's not all. Just like Roku, Etsy is running a hyper-effective business in its chosen niche.

No other e-commerce platform focuses exclusively on handmade craft items, pieces with vintage charm, and hard-to-find collectibles. Sure, you can find some of this stuff at eBay (EBAY) if you're lucky, but Etsy requires these qualities from every seller and every item.

Etsy's top-line sales are growing faster than Amazon, quicker than eBay, and swifter than almost any major e-tailer you might care to mention. The company is far smaller than many of those slower-moving rivals, but that only leaves more room for industry-leading sales growth in the long run.

Bargain-bin share price plus incredible growth potential equals another fantastic buying opportunity. You should consider Etsy before the next long-term bull market gets started.