Imagine Image offers the freeHex Command Ancients Rules for miniatures wargames. The hex system is supposed to simplify things and speed play. You can play without a hex board if you want.
Generic Near Eastern “Bronze Age/Biblical” Figures
Mike Schubert of the Pretoria Wargames Club has an article on which Essex miniature wargaming figures to use to build armies of obscure near eastern bronze age armies, such as the Mitannians, Canaanites, Later Hebrews and Neo-Hittites.
Little Lambent Meteors
Jim Wallman’s Little Lambent Meteors is a set of free wargames rules for 18th Century riots, using 15mm figures.
Road Warriors rules
Michael Taylor has written Road Warriors, a set of free wargames rules that uses Matchbox cars for games set in a post-apocalyptic future, ala Mad Max.