As we move closer to a bull market, you may be looking to add a few promising growth stocks to your portfolio. After all, these stocks often thrive during times of market optimism and expansion. So, today, it's a great idea to look for companies that not only have great long-term prospects but also have a potential growth catalyst (or catalysts) around the corner.

You might find candidates in any industry, but today I'll look at two biotech companies and one consumer goods company that truly stand out. Their revenue could skyrocket thanks to new projects unfolding right now, and considering their growth potential, they look very reasonably priced. Let's take a look at these potential winners...

1. Moderna

Moderna (MRNA 2.57%) today is known for its blockbuster coronavirus vaccine. But a few years from now, this biotech may become a multi-product company generating as much as $30 billion in annual revenue. The company said this week it plans on launching as many as 15 products in the next five years and bringing possibly 50 new candidates into clinical studies.

All of this means Moderna could see revenue take off this decade thanks to today's late-stage programs -- and if even a handful of the new candidates make it to the finish line, growth could continue well into the future.

The biotech company is using the strengths we saw as it developed its coronavirus vaccine to create a full respiratory vaccine franchise, including the coronavirus vaccine and potential vaccines for flu and respiratory syncytial virus (RSV). And Moderna's work in other areas such as oncology and rare diseases will broaden the revenue opportunity.

Trading at only 8 times forward earnings estimates, Moderna looks like a dirt cheap buy considering its potential for enormous growth just a few years away.

2. Vertex Pharmaceuticals

Vertex Pharmaceuticals (VRTX 1.17%) has built a leadership position in cystic fibrosis (CF) treatment, but just because it's a giant doesn't mean its growth is over. The company's latest treatment, Trikafta, led a 14% increase in product revenue in the most recent quarter. And Vertex is working on new CF treatments that could keep revenue climbing.

The biotech company also is expanding into other areas, and a key milestone lies just ahead. Vertex and partner CRISPR Therapeutics are awaiting a regulatory decision on their blood disorders candidate, exa-cel. The decision on exa-cel for sickle cell disease is set for December and the decision on beta thalassemia is set for March. Though the treatment may not generate as much in revenue as Vertex's CF treatments, it still is heading for blockbuster status and shows Vertex has what it takes to expand beyond CF.

Vertex also has other promising late-stage candidates in the pipeline, including ones for type 1 diabetes and pain management. So, this big biotech may see a lot more growth down the road, and that means, trading at 23 times forward earnings estimates, Vertex looks like a steal.

3. Chewy

Chewy (CHWY -1.42%) offers pet owners just about everything they need for their furry (or sometimes not so furry) friends. The e-commerce company sells food, supplies, pet medications, and more, and you can even sign up for a service that automatically reorders and delivers your favorite products right to your doorstep. This service, Autoship, makes up 75% of Chewy's overall sales, demonstrating the loyalty of Chewy customers.

Last year, Chewy reached the big milestone of profitability, and in the most recent quarter, the company showed its resilience even through tough economic times. In the quarter, net sales and net sales per active customer climbed in the double digits. The company also reported gains in free cash flow.

CHWY Free Cash Flow Chart

CHWY Free Cash Flow data by YCharts

All of this already offers us reason to be optimistic about Chewy. But a catalyst on the horizon could spur even more growth and eventually drive share price performance too. Chewy aims to expand into Canada in the third quarter of this year. This is a big deal because Chewy predicts that, in the Canadian market, it can reach the same levels of profitability and market share it's recorded in the U.S.

Chewy's shares have dropped more than 40% this year, offering investors an excellent opportunity to get in on what could be a huge growth story.