I know some of these guys are specific to the cantina and Jabba's Palace, but some could be seen just about everywhere in the Star Wars galaxy:
Gran (perhaps a new Senator)
Ishi Tibbs (not from the Rebel Alliance)
Quarren (perhaps a Separatist)
Gragga (Swokes Swokes)
the new aliens seen as Jedi and in Coruscant's entertainment district with the 3 points to their head (hard to describe)
Wookiees (that don't wear a Chewie-style bandolier like the Senator)
Trandoshans (that don't look like Bossk)
Falleen (that don't look like Xizor)
Kaminoans (who aren't Lama Su or Taun We)
What other aliens would you like to see made into action figures?
There actually doesn't seem to be THAT large of list.