OPs and EDs? It’s hard to choose, there are so many good ones.

Live songs? Yuru Yuri live events are peak seiyuu aidoru especially the first season OP and ED 😤

Insert songs? I really don’t know off the top of my head!

Songs sung by characters? THAT one from ARIA (not spoiling it). And the songs from K-ON! (also written by them). I also liked the graduation song from Non Non Biyori.

BGM? ARIA and Hidamiri Sketch have some OST that have vocals and are thus songs technically. Most of them don’t have lyrics but if we count it then I pick those.

Character songs? Probably more Yuru Yuri songs especially the live versions. Lucky Star has great ones especially those where they sing karaoke together.