Dozens of cryptocurrencies soared in value last year. But so far, 2025 has been a dud. Most major crypto assets have seen their valuations plummet this year.

That's tough news for those already invested. But if you've been thinking about adding more cryptocurrency to your portfolio, this looks like a great long-term buying opportunity.

Right now, two cryptocurrencies in particular look attractive for patient investors.

This pioneering cryptocurrency seems too good to ignore

No cryptocurrency portfolio is complete without exposure to Bitcoin (BTC -2.67%), the oldest and most valuable digital asset, And while many experts talk about its potential as an ecosystem play -- including potential growth avenues like peer-to-peer spending and artificial intelligence (AI) transactions -- what I really love is its existing potential as a store of value. This is a clear opportunity with the chance to analyze the hard numbers. And the result of that analysis should get you excited.

First off, what exactly is a store of value? In many ways, it's exactly what it sounds like: an asset that retains a value simply by itself. A traditional stock, for comparison, needs a business that generates cash flow to derive value. An asset like gold, meanwhile, retains its value simply by being gold. Bitcoin is no different.

Right now, both retail and institutional investors alike understand that the world assigns a certain value to gold. And while that value may fluctuate, the precious metal is expected to retain a significant portion of its value for years to come, if not decades. This faith in gold has granted it a total market cap of about $20 trillion.

Bitcoin is earlier in its journey as a store of value, and many investors are still skeptical of its societal worth. That's why, for now, its total market cap is less than $2 trillion.

Based on these numbers alone, the cryptocurrency could be worth 10 times its current valuation if the gap between it and gold narrows over the long term. The recent decline -- which saw Bitcoin's price fall while gold's value rose -- has created an attractive buying opportunity for those bullish on its long-term adoption by global investors.

Is Ethereum superior to Bitcoin?

But what about betting on cryptocurrencies apart from their potential as a store of value? For that, check out Ethereum (ETH -2.28%). Although there are many competing networks and projects, Ethereum has a durable competitive advantage that will be hard to overcome: a strong and growing ecosystem of developers.

It arguably has some attractiveness as a store of value, but most of its value will be derived from long-term use of its network. That requires apps, services, and even other networks to be built on top of it.

All of that requires developers, and Ethereum has a healthy lead on the competition. Estimates vary, but roughly 6,000 developers now contribute to Ethereum and its associated projects built on its network. Solana, for comparison, has only a tenth as many.

When it comes to building a network with real long-term adoption, a vibrant developer community is one of the best indicators. And Ethereum's lead will be very difficult to overcome, especially given that developers want to build on networks that will be used by others, creating a positive feedback loop for the crypto's long-term development.

As a more mature project, there may not be as much near-term upside to Ethereum versus other projects with smaller valuations. But if I'm betting on any other cryptocurrency besides Bitcoin for the long term, it would be Ethereum.