It’s not clear what sort of music you want to play. If you want to play popular songs, then you are more limited to the likes of Galway Girl, Maggie Mae, Mandolin Wind, etc, but if you want to get away from essentially chord based stuff and play tunes, then there are dozens of good tune books, largely derived from traditional fiddle tunes, but readily playable on mandolin (same tuning even). At one time you had to be able to read the dots of course, but these days many have tablature (fret fingering) shown.