If you're looking for candidates for your long-term stock portfolio, consider growth stocks. They're tied to companies that are growing at a faster-than-average clip, and many of them will deliver terrific returns over the years and decades to come. Not all will, of course, which is why you'll probably want to spread your dollars across a bunch of them. Our Foolish philosophy suggests at least 25 stocks per portfolio.

Here are brief introductions to three growth stocks to consider. See if any or all of them interest you.

1. Nvidia

Semiconductor giant Nvidia (NVDA 4.09%) specializes in graphics processing units (GPUs) that are used by gaming systems, cloud computing operations, data centers, and others. It's also a major player in the artificial intelligence (AI) realm and "accelerates" various applications, making them more effective.

Check out these impressive stats from the company, showing how widespread the use of its offerings is:

  • "NVIDIA DRIVE powers all 30 of the 30 top autonomous vehicle data centers."
  • "More than 200 million gamers and creators use NVIDIA GeForce GPUs."
  • "More than 600,000 developers have downloaded the MONAI framework for AI in healthcare imaging."

Nvidia has been a phenomenal stock performer, rising in value by an annual average of more than 54% over the past decade -- and it's not bargain-priced right now, with its recent forward-looking price-to-earnings (P/E) ratio of 54 well above its five-year average of 40, and its price-to-sales ratio on the steep side, too.

Nvidia is facing some challenges right now, with a weak PC market and slipping gaming-chip sales, so it's not an attractive short-term investment. (Its fourth-quarter revenue slipped 21% year over year.) But there's plenty of promise for the long term. To play it safe, add the company to your watch list -- or, if you really want to own shares sooner, perhaps buy into the stock incrementally over time.

2. Zscaler

Zscaler (ZS -1.37%) has been another solid performer, averaging annual growth of nearly 27% over the past five years. The company is known for its Zscaler Zero Trust Exchange and boasts "the largest security cloud on the planet" -- that "protects thousands of customers from cyberattacks and data loss by securely connecting users, devices, and applications in any location."

Talk is cheap, though, so check out these results: In the company's second quarter, it reported revenue up 52% year over year, with net losses lower than the year before and lower than expected. Calculated billings, meanwhile, rose 34%.

The stock was recently down about 57% from its 52-week high, reflecting the company facing an uncertain economic environment, with many companies not spending freely. Its long-term prospects seem solid, though, as it's a leader in cloud-based security, and demand for that doesn't seem like it's going away anytime soon.

Those aiming to hold their stocks for many years should consider Zscaler, as it's poised to prosper over the long run. At a minimum, add it to your watch list.

3. Digital Realty Trust

Digital Realty Trust (DLR 0.80%) is a real estate investment trust (REIT). REITs offer investors a handy way to invest in real estate without having to own actual properties. Instead, the REIT buys and owns lots of properties (often in one or more particular niches, such as apartment buildings, medical facilities, or retail spaces), collecting rental income from tenants. By law, REITs must then return at least 90% of taxable earnings to shareholders, typically via dividends.

Digital Realty Trust's focus is on data centers; it owns more than 300 of them and aims to keep investing in more. Its customers include many familiar names, such as IBM, Oracle, Meta Platforms, Verizon Communications, and Comcast. The company operates in dozens of metropolitan areas across the globe, and has been expanding internationally, often via acquisition.

For 2022, the company (referring to itself as "the largest global provider of cloud- and carrier-neutral data center, colocation and interconnection solutions") posted revenue up 10.6% year over year (in constant currency) and a record backlog of $477 million -- about 60% of which would start in 2023. The company also signed more than half a billion dollars' worth of new leases.

One of many appealing things about Digital Realty Trust is its dividend, which recently yielded a hefty 4.6% -- as the stock was recently down some 33% from its 52-week high. The company has boosted its payout in each of the past 17 years, averaging annual increases of 10%.

These are just three of many compelling companies out there with lots of long-term growth potential. If any interest you, read more about them and see whether you think they deserve berths in your portfolio now or in the near future.