The bots I notice on my server are always DKs, DHs and Druids in tank specs, since they can't be dazed.
There's also this problem with nodes that are ungatherable but don't despawn, I have a suspicion they bug out because of bots mining them from underground or something.
Recently I encountered such a bugged felslate node, tried to mine it but it wasn't lootable, I gave up after a couple of tries and then I stood there witnessing 2 bots hitting at it repeatedly for at least 5 minutes, reported both and left. Any human being would realize this node doesn't work, it's futile to keep mining at it. A bot doesn't think, so gets stuck in a loop.
They're also a plague of any premade group with auto invite, you join any group for world boss or something only to see 15 tank specced druids / DHs / DKs trying to realm hop despite it doesn't even work because they're in Suramar while the group isn't (so it won't even phase them since 7.0 changes to realm hopping).
But yeah, I could think realm hopping is not a give away of a bot, but mindlessly hacking at a bugged node obviously being stuck in a loop is a dead giveaway of a bot. No one can tell me "oh but these are legit miners", even most dense human being would give up after 10-20 tries...