Foul Play - an move that uses the opponent's attack stat to deal damage.
Taunt - a move that prevent's the opponent from using attacking moves.
Beat Up - a move that hits up to 6 times based on the stats of your party members.
Knock Off - a move that cripples the opponent by removing its held item + does more damage if they are holding an item.
Torment - a move that prevents a Pokemon from using the same move twice in a row.
I just wish other types had such a wide variety of moves! I know Dark types are supposed to be dirty fighters and their moves reflect this, but it would be awesome if other types got such awesome effects as well!
Knock off got a sick buff this gen. I only wish it's more widely available.
To be fair I think its a bit TOO strong right now. Knock Off was already pretty common before the damage buff. Removing an opponent's item is super crippling to some Pokemon who are really dependent on them.