A lot of good fun stuff already mentioned, so I'll try not to go over ground that's already covered. Some other stuff I enjoy:

Leashes/collars: Very basic for most of us. It was the first "BDSM symbol" I really identified with and they do make me hot.

Pet play: Get down on all fours, crawl around, bark, eat out of a dish, give sexual favours. That's the ticket. I wouldn't want do do it absolutely full time but in doses it is great stuff.

Beastiality: Related though also quite different from the above. Not everyone's cup of tea and I'd enver pressure someone to get into it if it grossed them out. But since we've got knife play, fire play, and rape play all floating around, this is hardly a step any further into the extreme.

Subs who take their orders with a little bit of atitude once in a while.

A lot of different outfits/costumes.

Tons of other stuff too lol... some of it already mentioned some I just haven't thought of right now. If it feels good to you, do it!