Films?
I know ZachWZ wanted book ideas, but I'd be interested if anyone knows any 'Live-Action' as opposed to animated films concerning shrinking and small people.
These are the ones that I know of:
Honey I Shrunk the Kids - (1989) A bumbling inventor inadvertently shrinks his own children then throws them out with the trash. They, along with the neighbour kids, must journey back across their own backyard to get back to the right height. [Dir: Joe Johnson, Cast: Rick Moranis, Matt Fewer.]
Inner Space - (1987) A pilot is miniaturized and then accidentally injected into a timid grocery store clerk. Together, the must prevent thieves who want to steal the formula. [Dir: Joe Dante, Cast: Dennis Quaid, Martin Short.]
Fantastic Voyage - (1966) A team of doctors and a submarine are miniaturized an injected into a top scientist to save his life. [Dir: Richard Fleischer, Cast: Stephen Boyd, Raquel Welsh, Edmond O'Brien, Donald Pleasence.]
Tom Thumb - (1958) Comedy. A tiny forest boy outwits some thieves. [Dir: George Pal, Cast: Russ Tamblyn, Jessie Matthews, Peter Sellers, Terry Thomas.]
Incredible Shrinking Man, The - (1957) After being caught in a radioactive mist and man shrinks inexorably to micro-size. [Dir: Jack Arnold, Cast: Grant Williams, Randy Stuart.] Based on the Richard Matheson book.
Girl in his Pocket - (1957) An eccentric scientist discovers a method for shrinking people, and uses his girlfriend as a guinea pig. A French sci-fi comedy. [Cast: Jean Marais, Genevieve Page, Jean Claude Brialy.]
Devil Doll, The - (1936) A man who escapes from Devil's Island disguises himself as an old lady who sells human dolls which murder those responsible for his imprisonment. The doll is created by a shrinking process. [Dir: Todd Browning, Cast: Lionel Barrymore, Maureen O'Sulivan.]
I've seen all those except the French film 'Girl in his Pocket'.
On TV there was also Irwin Allen's 'Land of the Giants'. Jonathan Swift's book 'Gulliver's Travels' includes the small people of Lilliput, but I think any attempts to film that political novel have been animations aimed at children.