There are many open-source games. There are few large-scale high-polish open source games because it's difficult to build a business model around that. Unlike non-game software, games are ~exclusively consumer-facing, so you can't sell support or use them as a loss leader, and they're standalone applications that are difficult to monetize with online features or to use as the core of a closed-source commercial product.
That said, there are still lots of great projects out there (some of which have even had commercial success), for example:
I think this is just stupid question, but I wonder in FOSS there is no game project that created from active community for alternative of another game. When we face a problem like paid software or problematic software that steal our data, the community will make the alterative for us but it is less possible for game generally.
That said, there are still lots of great projects out there (some of which have even had commercial success), for example:
- https://github.com/a327ex/SNKRX
- https://github.com/beyond-all-reason/Beyond-All-Reason
- https://github.com/endless-sky/endless-sky
- https://github.com/Anuken/Mindustry