If you're a fan of growth investing, you know it makes sense to look for companies you can buy as they're just starting to break away from the pack, then sell when they can no longer deliver good results for shareholders. When a stock is popular, it can give investors confidence that their holdings will be secure -- at least for the near term -- thanks to the influx of other buyers who have been impressed by the company's results.

All three companies I'll mention today -- a video game developer, a conglomerate building 5G networks, and a coronavirus vaccine manufacturer -- have significant potential to reward investors for the long term. Let's take a look at why you should consider each one. 

Dollar bills showering down while a man cheers.

Image source: Getty Images.

1. Zynga

Up 51% year to date, social video game developer Zynga (ZNGA) has captivated investors with its financial performance. The COVID-19 pandemic and its accompanying stay-at-home orders have led people to allocate more of their entertainment budgets to online games. As a result, Zynga now has more than 70 million active users who spend approximately $0.248 each per day on its games, a massive increase over the $0.188 it had in average revenue per user (ARPU) last year. 

For the full 2020 fiscal year, Zynga expects to generate $1.8 billion in revenue, which is about $500 million more than it had in 2019. The company is also growing at a profitable rate, with about $157 million in free cash flow (FCF) over the past 12 months. For those who are interested in growth stocks trading at a reasonable price, Zynga's 5.6 price-to-sales (P/S) valuation makes it a great choice.  

2. Corning 

Corning (GLW 0.12%) is a diversified life sciences and industrial company that provides optical communication solutions for 5G carriers. The company is currently working with Qualcomm (QCOM 1.10%) to deliver efficient indoor 5G networks. During the second quarter of 2020, Corning's revenue and adjusted earnings per share (EPS) increased by 7% and 25% compared to first-quarter 2020, to $2.6 billion and $0.25 respectively.

In addition, Corning recently received a $204 million grant from the Biomedical Advanced Research and Development Authority (BARDA) to increase the production capacity of its pharmaceutical glass vials, which are used to make COVID-19 vaccines and drugs.

That's not all; Corning is also witnessing increased demand for specialty materials for smartphones, with sales up 13% year over year, and for the automotive particulate filters and TV displays it manufactures.

The good news is that Corning stock is incredibly cheap when considered against all its potential. The company trades for just 2.7 times sales and 29 times free cash flow while having a debt-to-equity ratio of only 0.35. For investors who are passionate about 5G stocks and are looking for players with ample diversification, Corning is a top pick. 

3. Novavax

In September, Novavax (NVAX 3.91%) was among the first companies seeking a coronavirus vaccine candidate to publish peer-review clinical data from a phase 1 clinical trial, which it did in the New England Journal of Medicine. The results demonstrated that NVX-CoV2373, its recombinant (DNA-encoded) coronavirus vaccine, effectively provided immunity against the SARS-CoV-2 virus in a small sample.

Based on the results, the company was able to convince the government of Canada to purchase 76 million doses of its experimental vaccine, contingent on late-stage trials' success. NVX-CoV2373 is currently in a phase 2/3 study.

By mid-2021, Novavax will have the capacity to produce 2 billion doses of its coronavirus vaccine should it do well in clinical testing. That's good news for investors because Novavax only has a $6.8 billion market cap, unlike many other sector players. Even if the company prices its vaccines cheaply -- say, at $10 per dose -- it could potentially generate $20 billion in annual sales. If biotech investors are looking for a good coronavirus vaccine stock, Novavax is among the cheapest out there.