If you're 130 or above, join 0bbyknights (starts with a zero). If you're 100-129, join obbysquires. I don't know any other good clans, but I use 0bbyknights myself, and in the time I've used them, they never made a wrong call (20+ games)
if you just stand in the lobby, then youll often find people advertising clans, i havent been there since 99 str (months ago) so im not really with the clans.
There are differnt clans for each world and each have differnet level requirements. If you play legit join a high levle one for switches. If just botting join any that call becasue bots dont take in switches.