If you've missed out on stocks that crashed in March and that have already produced significant returns in April, don't fret, as there are still many good opportunities today.

While it may take some time to earn strong returns given the uncertainty surrounding the COVID-19 pandemic and its impact on global economies, the stocks listed below are great options to buy and hold. They even have the potential to double in value.

1. Aphria

Aphria (NYSE:APHA) is one of the better Canadian pot stocks. The company has posted a profit in three of its past four quarters, and it has a healthy cash balance that's actually been growing in recent periods. The stock also trades at a modest two times its sales -- which is a downright bargain compared to industry giant Canopy Growth's (NYSE:CGC) P/S ratio of nearly 20. 

What's surprising is that amid these positive results, the stock is still down 55% over the past 12 months. While it's better than how the Horizons Marijuana Life Sciences ETF has performed during this period (down 69%), it's still an atrocious return for a stock that deserves a much better fate. But that's also what makes it a great buy today -- the stock's potential for rebound.

A bar chart drawn in chalk showing values getting bigger

Image source: Getty Images.

The biggest obstacle to the stock's turnaround is the adversity faced by the broader cannabis industry. There are many fears that pot stocks will crumble and go bankrupt this year. And even though Aphria doesn't belong to that group of high-risk stocks, pot stocks often move in unison.

The industry needs some positivity to rally around, and any good news that occurs may end up being the catalyst Aphria's stock needs to soar to double, or perhaps even triple from today's price. Investors who are patient enough could be rewarded with impressive returns if they buy shares of Aphria today.

2. Square

Square (NYSE:SQ) is an appealing buy for many reasons. What's great about its business is the simplicity of a merchant being able to accept credit cards even if they're a novice without experience using credit card terminals or point-of-sale devices. The company's card readers make it easy for anyone to set up shop anywhere, which may become an even more important feature in an era of social distancing.

The company has already achieved significant growth. In 2019, sales of $4.7 billion were up 43% from the $3.3 billion in revenue Square recorded in 2018. While its transaction-based revenue continued to grow at a rate of 25%, the company's subscription and service-based revenue soared by 74%. The two segments combined to make up 87% of the company's top line in 2019, which is down from 93% in 2018. The area that saw the most growth was perhaps the most volatile: Bitcoin revenue. Sales from this segment totaled $516.5 million and were more than triple their prior-year total of $166.5 million.

Prior to the outbreak of COVID-19, the company said on its 2019 Q4 earnings call that it was expecting revenue for 2020 to fall in the range of $5.90 billion to $5.96 billion, which would deliver growth of about 26%. However, that's likely to change as a result of the pandemic.

Regardless of what happens in the short term related to the economy, what's evident is that there's a lot of potential over the long term. Like Aphria, this is another stock that may need a catalyst to get it going, and it's not likely to get that from a strong earnings report anytime soon due to the slowdown in the economy. In the past year, shares of Square are down 14%, while the S&P 500 has declined by 3.6%.

Which stock is the better buy?

Both stocks listed here could double; it's really just a matter of how long it will take for that to happen. Pot stocks are a volatile bunch, and while that makes Aphria the riskier of the two stocks, it also makes it more likely to spike in value much sooner. For investors who are looking to minimize their risk, though, Square's the better choice today.

Regardless of which stock investors choose to buy, they'll have to remain patient, as there's little reason to be bullish in the near future with the pandemic still weighing down many stocks and industries.