Nights of the Crusades is an RPG that’s gotten lots of good reviews. The good news is that the pdf is free.
Machinations is a simple steampunk RPG. From the author’s description:
Welcome to the Eternal City, the home of the Machinations RPG. Take on the role of an Adventurer, an Alchemist, an Artificer or even a deathless Automaton. Band together with others to form a Free Company and then hire yourselves out to perform acts of sabotage, espionage, assassination, extortion, blackmail or plain old robbery. All in a world a short step from our own, where reason has been lost, empires exist to be built and strange technology dominates all walks of life. It is a world of sinister intrigue, awful power, terrible events and dark portents. There is also beer, song and glory
Dark City Games’ Legends of the Untamed West is a tactical RPG for the 1800s American West. The system is based on the wonderful Fantasy Trip system that originally was published in the micro games format. If you’re familiar with the Fantasy Trip, you know that it makes for just as good a miniatures system as an RPG.
You can’t get the Fantasy Trip any more, but you can get Dark City Games’ Legends of the Ancient World, a free tactical RPG that uses the same mechanics.
Mobsters is a set of roleplaying rules for 1920s gangsters. It’s a well-done and complete game.