Cannonade is a Napoleonic era board style wargame designed to be played on a hex board. While the board isn’t provided, the game does include counters for you to print out.
Hex Command Gunpowder are a set of free wargames rules for the horse and musket era. They are designed for a 1 stand = 100 men scale. The authors write:
These rules were designed to bring a simplification to wargaming with miniatures because it resembles a board game more than a complicated historical simulation. These rules are intended for any horse and musket era and with slight modifications can be used for any conflict in that range.
These rules do not consider formations as influencing the outcome of battle, other than if a unit is ordered or disordered, because the system compensates for the effects of various tactical realities. The game is intended to be played on hex grid pattern of 4 inch hexes, though this is
not required (numbering each hex is essential for playing via the internet), with the top left corner being a whole hex, and the hexagon orientation being that the flat top and bottom are parallel with the long sides of the surface (hexes are not “pointed up”). Game Mapper is
recommended to assist scenario creation and game tracking.
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.
Hohenfriedeberg is a free board game of the print-and-play, hex-and-counter variety. It depicts the battle of Hohenfriedeberg, which took place during the Second Silesian War in 1745.
Lance Runolfsson offers Sci Fi Strat, a set of hex-based science fiction miniatures rules.