Samhain - I call her Main, Wain, Bain, Main-y, Main-y-o, Samhain-y, Samhain-y-o, Medicine Head (because when she was a kitten we had to give her medicine and we sucked at it and got it all over her head), Pepperoni Back (because she bumped me when I was eating pizza and she got pepperoni on her back), Toothpaste Tail (she snuck under my toothpaste spit and almost got out on time) and I call her "my girl"...
Mitzi - Mitz, Mit-zues, Zues, Buzz-zeus, Buzz, Mitsu, Buzzu, Moo
Psi - "Little Psi" is my only nickname for him so far because he is just a kitten, but sometimes I call him BRAT.