Weavile is a good option. It has amazing Speed and Attack and has a nice typing which is Dark-Ice. Another option is Absol, with its Super Luck ability and Night Slash, you might get a critical Hit almost every time, but it lacks Speed. My last option is Drapion. It has an amazing typing, with Is Dark- Poison and it has a bunch of moves that can strengthen your team further, which is great :D