Here are a basic set of free wargames rules for skirmishes set in the French and Indian War.
Miniatures Rules
God Will Know His Own: Rules For Knight and Crossbow era 1096-1590 (or 1789)
God Will Know His Own is a set of free wargames rules for “Knight and Crossbow era Wargame Rules 1096-1590(or 1789) then into the horse and Musket era.”
Empire Knightly Orders Army Book For Warhammer
Here’s a fan-created Warhammer Fantasy Army book for the Empire Knightly Orders. As with the others in this series, it’s very well done.
Army Dudes Plastic Army Men Rules
Army Dudes is a set of free wargames rules for playing games with the classic green army men.
Focused Firepower WWII Rules
Focused Firepower is a set of free wargames rules for playing WWII skirmish games. The authors write:
Focused Firepower is a scenario-driven 1:1 wargame designed for use with 1/72 scale miniatures. We have endeavoured to offer an in-depth game system with the focus on realism, but the system we have developed is easy to learn and games flow well.
As a 1:1 system the models you have on the tabletop represent the exact troops and vehicles. The majority of other game systems use a more abstract method where one unit actually represents several, or where entire units are modelled on a single base and dealt with as a whole. We found that our method provides a more accurate and realistic impression of real warfare.
By focusing our game on realism we have found that real-world tactics work just as well on the tabletop and we highly recommend reading the fantastic range of WWII tactics books published by Osprey.