It's so good to see themes being resurrected. While I'll rarely be able to participate, here's some suggestions:
One word titles
Numbers
Sexual Euphemisms
Cover tracks
Colours
Professions
Astronomy
Songs / Artists with a literary reference
___ and ___ ("Us and Them", "And You and I", "Me and You and a Dog Named Boo" - Wait, is that on the playlist?)
Geographical features
You'd better stop me now....