The phrase "a growing crowd of" is correct and usable in written English.
It can be used to describe an increasing number of people gathering in a specific location or for a particular event.
Example: "As the concert time approached, a growing crowd of fans began to fill the venue."
Alternatives: "an increasing number of" or "a rising group of".
Outside the hospital, Ms. Santillán's parents hugged in front of a growing crowd of reporters.
It's fending off a growing crowd of agitated investors, who are calling on the company to explore strategic options.
Pure Storage is joining a growing crowd of start-ups seeking to bring flash storage to the data-center market.
Earthlink, the second-largest Internet service provider, has joined a growing crowd of companies that have appointed chief privacy officers.
The hot-dog stand had turned into Le Pain Quotidien, and we joined a growing crowd of refugees from the storm, huddled on the covered patio.
We were waiting next to a sign that read, "Track closed due to avalanche danger," while a growing crowd of hikers accumulated behind us.
They took me up to a podium playing a French song about chickens as a quickly growing crowd of passersby assembled to watch, point and laugh at me.
Naturally, the rainy-day chase ended on a narrow residential street with two suspects sharing hugs and handshakes with a growing crowd — and lots of selfies.
Naturally, the April 2016 rainy-day chase ended on a narrow residential street with two suspects sharing hugs and handshakes with a growing crowd — and lots of selfies.
It became clear that CTU was working quickly to publicize their stand, he described, as sounds of a growing crowd came from another part of the union building.
In one – "Weapons of Math Destruction" – a former hedge-fund quantitative analyst, now an organizer with Occupy Wall Street's Alternative Banking group, talked to a growing crowd about the abuse of mathematical modeling in the financial industry.
