Pz8 is a series of two-page wargames rules. Among them are is a set of free wargames rules for coastal actions.
rules
Giant Stompy Robots Rules
Meca Tac – The Giant Stompy Robots Edition is a set of free wargames rules for Mecha battles.
King Of War Historical Ancient Battles
The Hour of Wolves and Shattered Shields site has a set of free wargames rules for Ancients Battles based on the free set of fantasy wargames rules called Kings of War.
Free Elements LITE RPG
Free Elements LITE is a starter version of a more complex RPG where, according to the author:
This system utilizes the Elements TTRPG system, which is a freeform action system. You perform actions by describing what you want to do, and picking a skill to use. Based on that skill’s rank, check your multiplier table to see how many points it has. All checks require skill rolls from both parties to determine the success rate, regardless of what the target may be, you’ll engage in a battle of skill checks with it. If you don’t have the proper skill, you must perform an untrained skill check with it. Rate of success when performing an action determines the outcome of a battle, if successful enough the DM will allow you to describe the outcome, where if you’re within 9pts of each other’s checks the DM will describe what happens instead.