Another project that would certainly benefit from crowdsourcing is the OpenMetroMaps[1]. Lack of the good universal public transportation website and mobile app is disheartening. I know there's is Transportr[2][3] but it's coverage is still pretty limited.

[1] https://github.com/OpenMetroMaps

[2] https://transportr.app/

[3] https://github.com/grote/Transportr