I'm just wondering where all the Super Mutants are! I've been and done Black Mountain but I haven't seen any apart from there. I just seem to be running out of monsters to kill...

EDIT: Super mutants that I can kill. [Hostile ones unlike Westside and Jacobstown]

REPCONN Test Facility (or whatever it's called, west of Novac) has Nightkins.
There's a cave north-west-west of Old Lady Gibson's house that has some Nightkin.
There's a super mutant camp to the most north-eastern part of the map (with some centaurs in a big crater just south of this camp).
Black Mountain.
Jacobstown (northeastern part of map in the mountains.).

Don't forget Jack Rabbit Springs near Nipton.

There's a small campfire group of them...uh...northish of Bitter Springs? Near one of the NCR outposts I think? (edit:oh wait Gab already mentioned it, misread...). But yeah, they're not plentiful, and I'm not sure if they respawn outside of Black Mountain. I don't tend to go back to the out of the way corners too often.

Also....

That's what a new character/game is for.

There's one in westside I belive