Depending on tank size, most tiger barbs kept in a nice school (5-6) are usually docile. You'll want to avoid anything with extravagant finnage, and usually slower swimming fish. Tiger barbs are an active fish, and you should try and get something that can be active with them. Most tetras should be fine, rasboras, danios, cories, mollies, platies. I'd shy away from guppies, bettas, angels, etc.
Good luck.