My go to's are usually 80's or 90's pop/hip hop (La Bouche, Salt & Pepa, N'SYNC), drag queen music, or unheard of pop/hip hop songs. My kids danced to Stop Sign by Angelique Sabrina last year and it was fab. In high school I danced to Be My Lover by La Bouche and that was also awesome. I just did dances to Freeze by Chris Brown/T-Pain and Lose My Breath by Beyonce.
Unfortunately, if someone has a great, unique dance song...they probably won't share it.