Prolific games designer Rudi Geudens offers Afriboria, a fast play, card driven set of colonial rules. What’s really neat about this game is that Rudi has designed some gorgeous custom cards, as well as labels to stick to six sided dice for use with the game.
Matakishi has written The Natives Are Restless Tonight, a set of free wargaming siege rules for any game involving a large band of natives, and a small, but stalwart group of westerners. They would work for any game in the colonial era, including the Zulu War, Boxer Rebellion, Foreign Legion, North West Frontier and Indian Mutiny.
The rules use a card activation system, and involve rolling handfulls d6s. Casualties are determined by summing the attack dice and removing a figure for every multiple of 6, 9 or 12, depending upon the defensive situation.
Tanzanica is a set of free wargames rules for Darkest Africa adventures by Brett Abbott. The rules actually are a variant of Games Workshop’s Mordheim miniatures rules, which are themselves free at the Games Workshop living rules archive. Mordheim is a neat set of rules for the kind of game where each player controls a small group of characters, with one uber-character and several flunkies.
Free Colonial Skirmish miniatures rules from the prolific Steve Winter: Stand To!