*There was TC-14 on the Trade Federation ship in TPM
*Another cybot galactica protocol droid was on Tantive 4 behind 3PO
*There was R-3PO (the red one) at echo base.
*There was U-3PO (the white one) at echo base.
*There was the "familiar face" at Bespin who said "E Chu Ta."
I do not recall any others.