Look up the word "monster" and you'll come across two key definitions -- "a large, ugly, and frightening imaginary creature" and "a thing of extraordinary or daunting size." So when we speak of monster stocks, we typically refer to the latter definition (although we may sometimes refer to the former).

Here then are four monster stocks of the extraordinary kind, including some you may want to buy and hang on to for the coming 10 years.

A robot doing calculations on a blackboard.

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1. Lululemon Athletica

Let's start with Lululemon Athletica (LULU -0.06%), maker of athletic apparel and shoes. Its stock has a somewhat monsterish long-term performance record, averaging annual gains of about 15% over the past 15 years. But the shorter-term returns are monsterish in the other sense of the word -- averaging annual losses of 11.6% over the past five years.

The big question is whether it will deliver for shareholders going forward, and it has a good chance of doing so. Indeed, some think the stock is cheap, since it's growing well abroad (including populous China) and has inked a partnership with American Express that could drive more growth. The company also has strong pricing power due to its brand, and it has a strong balance sheet.

Of course, tariffs are a concern, and the company's growth has been slowing. So do more research before jumping into the stock, and weigh its pros and cons.

2. Amazon.com

Amazon.com (AMZN 0.91%) is perhaps obviously a monster stock, with average annual gains of nearly 25% over the past 15 years. There's much more to the company than its massive online marketplace, too.

For example, it's a leader in the cloud computing space, with its dominant Amazon Web Services (AWS) platform. While the marketplace generates the most revenue, that revenue features relatively low profit margins. Amazon's digital advertising business and AWS, meanwhile, are higher-margin operations.

With a recent forward-looking price-to-earnings (P/E) ratio of 28.2, well below its five-year average of 45.5, Amazon's stock seems attractively valued. Is it likely to grow for you in the years to come? It sure seems so. It's playing a long game, as it invests in artificial intelligence (AI) technology and its AWS platform, designing its own chips and building more data centers.

3. The Metals Company

The Metals Company (TMC -7.27%) is not a household name, but it does sport a monster track record, up about 500% over the past year and averaging annual gains of 82% over the past three years. (It has only been public since 2021.)

Its goals are monstrous, too. Its website says: "The Metals Company is developing the world's largest estimated resource of metals required for electric vehicles and low-carbon energy." These metals include nickel, copper, manganese, and cobalt, and it's looking to harvest them via deep-sea mining.

Per the company's latest earnings report, it's not profitable at this point, reporting no second-quarter revenue. Investors need to do enough research into the company to see if they believe that it will achieve its goals. Perhaps they might just wait and see, adding the stock to a watch list.

In the company's favor, the Trump administration is promoting deep-sea mining. So give this high-risk, high-potential-reward company some consideration.

4. Broadcom

Broadcom (AVGO 0.84%) doesn't get the love that fellow semiconductor company Nvidia does. But it's a monster stock, too, with a recent market value near $1.6 trillion and average annual gains of nearly 40% over the past 15 years.

This company specializes not only in semiconductor chips but also software -- and its very diversified operations include wireless and wired technology, optical products, mainframe software, cybersecurity, and storage, among many others. Its offerings are needed for AI operations, and it's designing custom AI chips.

The stock doesn't appear cheap at recent levels (it hit an all-time high recently). But it's been growing very rapidly, which justifies at least some of its valuation. Anyone aiming to hold the stock for many years could do well buying into it now -- after learning more about it, of course.

Give any or all of these stocks some consideration for berths in your long-term portfolio.