Seems like every week over on GamingOnLinux there’s an announcement of a new launcher.
Personally I only use Steam & Lutris. Lutris for my gog games and BattleNet, Steam for everything else.
I don’t know of a good reason to use Heroic, or any of the other new ones over Lutris / Steam, but maybe I’m missing out.
Steam and sometimes bottles. But since you can add non steam apps its basically only steam when it comes to gaming.