Hordes of the Things (HotT) is WRG's cheap, simple yet excellent generic fantasy battle rules. You typically only need 40 or so figures for a game, which will usually take less than an hour to play. Unlike in modern Games Workshop products, magic isn't very "important" in HotT. This annoys some people, but is one of the main attractions for me. A general of an army has no business trying to decide in the heat of battle exactly what spells Goodgulf the wizard over on the left flank should be casting!
By far the best website covering HotT is 'The Stronghold'. If you don't know what HotT is all about, check it out! One of the authors of the rules, Richard Bodley Scott, has a small official web-site devoted to the game which can also be usefully consulted. John Garvey has an interesting site detailing South American fantasy wargaming.
The links below detail army lists I have designed for HotT.
36 Middle-Earth army lists
Paired Japanese army lists from 3 different eras
Two paired Jewish Apocalyptic lists