There's been many. A lot have already been named so I'll try to add some new ones. Hair, there has been plenty of times I've sat behind a female friend or crush and tickled her with her own hair. Whether on her neck, her arm or her lower back. I've tickled with a led pencil, by pretending to write something on their naval, thigh or foot than erasing and starting over again because I "misspelled" a word or two. And anything that vibrates, the mini massages they would sell at Rite Aid or CVS, I would take one and run it across their entire back, legs and sometimes even a foot while we waited on line, I also used by sell phone(back when their vibrations were ridiculously high) and tickle them all over with that as well. There were even a few times female friends or girlfriends would have a dog and I would use the dog to lick their feet to get a ticklish reaction, one time when I was on the phone talking to an ex, she randomly began laughing and when I asked what was so funny she explained to me her Pomeranian jumped on the bed and began licking her foot. Middle and high school were so much fun.