Top of my list is Mad Max. Preferably Road Warrior version. His Dog would make a great exclusive.
Next up would be Ripley from ALIENS decked out in the outfit and weapons during her rescue of Newt would be epic. An Alien egg exclusive would be killer.
Michael Myers from his days on Saturday Night Live..... just kidding. Halloween of course! Part 1 or 2, no Rob Zombie crap. How awesome would it be to have a jack-o'-lantern exclusive with flickering LED? The jack-o'-lantern should be just like the one from the opening title screen of the original Halloween.
Speaking of John Carpenter, finally I have to mention The Thing. There are too many great monster sequences in that movie to name them all but narrowing it down to two I would suggest either the Dog Thing in the kennel or the Norris Thing in full form. A Spider-Head Thing exclusive would work perfectly with either one of these.
I have more I'd love to see but those are at the top of my list. And with American Werewolf already underway that just about covers it for now.