I’m not exactly sure if this is what you mean, but I have a couple examples of fantastic community powered fan games that arguably eclipse their inspiration.

Pokemon Infinite Fusion: fan powered remake of Pokemon Fire Red that incorporates a fusion mechanic and has something like 600,000 high quality fan created sprites. They’re now working on a version for Pokemon Emerald

Clone Hero: fan made guitar hero/rockband clone with support for tons of peripherals including drums and vocals, with a huge library of fan generated songs.