"Swing Low Sweet Chariot" could be one. "Elvira" by the Oak Ridge Boys could be another, especially the part where it goes "oomp boppa oomp boppa mow mow mow" (If your voice is that deep I would have to question whether or not you are really female, or to recommend backing off of the testosterone treatments.) : D
Some of the songs that you can sing along to include In Love With Another Man - Jazmine Sullivan, Ready For Love/Brown Skin - Inidia Arie and Anastasia's songs. You can also try out some of the Me'Shell NdegeOcello songs as she has a deep voice with a great style or Amy Winehouse.