Smeargle should be mentioned. Like all the other Mystery Dungeon games the pokemon is in, it is essentially the king of the series. Since you are able to boost it's low stats far higher than ever and take advantage of any status, multi-hit or room wiping move that's available. Giving it the capability to dominate any dungeon that's in the game.

I thing exeggutor deserves a spot in this list too. Not only barrage is a multi-hit move but it can also hit pokemon in an arc much like a gravelerock

>>3 I'm the same as the guy beloww-- not syaing this is a bad thing I actually like it because I just want to explore and befriend all the pokemon in the game

>>2 yeah after that you just need patience and bring ample items into dungeons. you're good after that

>>1 Thats true. The game doesn't require much tactic after that point. Wishing they'd mix up the game little bit

As much as possible I keep 2 room-wide moves in my party and 2 long range ones. I can clear most dungeons with ease if that is my setup.