Welcome,
There used to be a set of alternate voices, but I’ve removed them starting with OpenEars 2.5 because it was a lot of work maintaining them through every packaging change required by Xcode, and ultimately every developer always ended up using the 16-bit SLT voice after testing the others because it sounded distinctly better than the other voices. You can adjust the Slt voice which ships with OpenEars to a male-sounding voice using the voice parameters available in OEFliteController and it will sound better than the alternate male voices did.