Adopt Me, a game about raising a virtual pet, recently saw more than million concurrent players. In May, it had a collaboration with Scoob!, the new Scooby-Doo movie. Players went wild baking bread that looked like characters from the game, just for a chance at a rare item. It regularly sees over 700,000 concurrent players, making it as popular as the most popular games on Steam, but you've probably haven't heard about it until this very moment.
This is a companion discussion topic for the original entry at https://www.vice.com/en_us/article/7kpm34/this-roblox-game-you-never-heard-of-is-more-popular-than-aaa-games-on-steam