If by "creatures" you mean wildlife/animals, here are some of the more common Star Wars creatures:
--Rancor, Reek, Acklay, Nexu, Dianoga, Taun-taun, Bantha, Dewback, Kouhon, Ysalamiri, Vornskr,...
The largest creature to appear in the Star Wars movies is a space slug. In episode 5 the millennium falcon hides in a cave of an asteroid to escape the imperial fleet, only to find that it isn't a...