GamePassport: awesome site to see current Game Pass titles, with filters for platform, genre, time to complete, and highlighting newly added and soon leaving games - eviltoast
Xbox Game Pass library browser | GamePassport
gamepassport.net
Find the next game to play with GamePassport, a convenient browser for the Xbox Game Pass library. Compare critic and user scores, filter by categories and features.

I’ve been using this site for a while now and it’s the best one I’ve found for discovering Xbox Game Pass titles.

I’m not affiliated with the site in any way. Just an enthusiastic user.