Foot fetish, spanking (both giving and receiving), tickling, sploshing, a bit of bum fun sometimes (rimming giving/receiving and sometimes anal when the mood strikes me, which isn't all that often), watching a girl smoke and receiving oral from her whilst she smokes.
Most of these things I've only really done with civvie partners though. I find it tricky and too much effort to really arrange to do this kinda stuff with a prossie. I have had a few good foot fetish type punts though, and engaged in spanking with most prossies I've met. Mostly, I'm pretty happy with a good vanilla punt though, and that's really what I focus on looking for.