Wolverine, Ashley Williams (Mass Effect Ashley, not Evil Dead Ash) and Sarah Lyons.
Wolverine is for those "We need a clear path from here to there, go nuts" type of situations. Ashley is the weapons lady. If we need a sniper or demolitions, we call her. And we know Sarah Lyons knows how to put teams together, start settlements, protect groups et al., so that kind of knowledge would be vital in starting a new settlement in a post-zombie apocalypse world.