Here's a few large/largeish projects I find interesting, in no particular order:

https://sr.ht/~mil/sxmo/

https://sr.ht/~thestr4ng3r/chiaki/

https://sr.ht/~alextee/zrythm/

https://sr.ht/~eliasnaur/gio/

https://sr.ht/~mil/mepo/

https://sr.ht/~etalab/code.gouv.fr/

Feel free to browse more here:

https://sr.ht/projects