Sometimes, all you need to make a killing is to own some growth stocks in your portfolio. As businesses are growing sales rapidly and arming themselves to make the most of the opportunities that lie ahead, growth stocks are primed to rise. If you're thinking tech stocks already, hold your horses and check out these three high-growth stocks that are just getting started, thanks to the huge underlying megatrends they're ready to ride.

Making a splash in e-commerce

Let's face it: Shopify (SHOP 1.25%) may look like an expensive stock. But we're talking about a hyper-growth company here that has come really far in a short span of time, and may have only scratched the surface of its addressable market.

By the end of 2015, Shopify had roughly 165,000 stores on its platform and reported gross merchandise volume (GMV) of $8 billion in the year. The same company now has more than 1.7 million merchants on its platform and ended 2020 with a whopping GMV of $120 billion. There's no stopping Shopify -- it recently delivered a bumper first quarter, with GMV and revenue growing 114% and 110%, respectively, year over year.

Two people appearing happy as they sit at a table and count money.

Image source: Getty Images.

Over the year, Shopify's global footprint and partner ecosystem grew as rapidly. Today, it allows merchants to market and sell through nearly every global channel, including Facebook, Walmart, and Snapchat, to name a few. It also has payments processing partnerships with the who's who in the industry, and even has its own logistics arm, Shopify Fulfillment Network (SFN).

Shopify's focus on expanding its international footprint and taking SFN and Shop App to the next level should fortify its position further, even as its "merchant-first" business model helps it capture an untapped portion of the global e-commerce market -- that of providing entrepreneurs and small businesses with all possible tools to sell their products and services worldwide.

Riding the future of energy

Brookfield Renewable (BEP -0.32%) (BEPC -1.56%) is sitting on a multi-trillion dollar addressable market that it's well prepared to exploit, and one that could catapult this top renewable energy growth stock to new heights.

So far, the rally in Brookfield's stock price was buoyed by growth in its dividends and funds from operations (FFO) per unit, which grew at a 10% compound annual rate between 2010 and 2020. With management now targeting 10% to 16% annualized growth in FFO through 2025 and 5% to 9% annual growth in the dividend, there's no reason why the stock price should not rise.

BEP Chart

BEP data by YCharts

Brookfield's game plan is crystal clear: Develop its monstrous existing renewables pipeline of nearly 23 gigawatts while adding to it opportunistically through acquisitions. Brookfield also wants to branch out further into solar and wind while capitalizing on its hydropower assets. So what we have here is one of the most diversified players in an industry with exponential potential. It's a more than $100 trillion multi-decade market in the making, which is exactly the kind of setting a growth stock investor would want to see.

First-mover in a monster market

After a stellar run-up for a year, Teladoc Health (TDOC -1.32%) shares have lost nearly 33% value in just the past three months. Investors have been wary of the company's ability to keep its cash registers ringing as the COVID-19 pandemic eases, but Teladoc is a company that's built to last.

Telehealth is all set to become a way of life simply because of the convenience it offers for both patients and healthcare providers. From routine checkups and specialist advice to acute care and chronic condition management, Teladoc covers nearly every aspect of virtual care. More than 50% of Fortune 500 companies are its clients, and Teladoc gets more than 20,000 visits on a typically busy day. No wonder Teladoc is churning big numbers -- its revenue catapulted 98% to cross $1 billion in 2020.

Granted, 2020 was an exceptional year as pandemic-induced lockdowns spurred demand for telemedicine, but even in its first quarter ended March 31, Teladoc reported a 151% jump in revenue and a 56% jump in total visits.

Here's why Teladoc's growth may have just started: Its revenue could double to $2 billion this year itself and hit new highs year after year, considering how telehealth is yet to take off globally. Teladoc's hunger for growth is already evidenced in its acquisitive strategy -- its recent $18.5 billion buyout of chronic-disease specialist Livongo is particularly notable and could be a game-changer. With McKinsey pegging virtual healthcare spending in the U.S. alone at a staggering $250 billion in the near term, Teladoc could be unstoppable.