Star Wars Episode VI: Return of the Jedi (1983)
Yes, we know – The Empire Strikes Back is the better film. But this is a list of alien films, and Return of the Jedi unquestionably has more (and better) aliens than any of the other original Star Wars movies. The Ewoks, the Rancor, Yoda and – of course – Jabba the Hutt all make for a veritable menagerie of alien critters. And all of them were created using awesome puppetry, unlike the glassy-eyed CGI abominations that people The Phantom Menace.