Sonic Heroes has some of the best music from any of the Sonic games imo, it has so many classics. Most of my picks will be from Sonic Heroes just by itself.

Casino Park is probably one of my favorite themes from them all.

Just hearing some of these songs again is making me want to play Sonic Heroes again! if only they would release it on Steam eventually

I also love the Sonic Colors main theme, including the orchestra version of it during the final boss.

Sonic Forces has some good music as well, the main theme and the ending song especially.