I will likely use this license: https://creativecommons.org/licenses/by-nc/4.0/

This basically just requires the game not be used for commercial purposes and that they provide attribution. So it's technically not an open-source license because it disallows the use of the project for commercial uses.

It also allows people contributing to mark their contributions as whatever license they want. So if you code or make something, you can license it however you want.

What does everyone think?