itch.io

You can launch linux container on a ChromeOS though.

It will be more tricky to set it up + Itch io app requires to be launched as appimage (self-contained app package) first, and manual install of game seems to be even less straigtforward if you are not a command line person (I don’t have ChromeOS, only linux, so I just looked over some guides and can only recommend to search them too)