The Men and Supermen Role Playing Game is designed to allow super powered characters to fight along side normal characters. In doing this the RPG takes on what I think is one of the most difficult of tasks — creating a common scale between units of disparate strength.
Under the Broken Moon is an RPG based on the Thundarr the Barbarian cartoon series. The game uses a mechanic where you roll a number of dice equal to your trait score and sum the results.
Death or Glory uses a percentile dice system and has medieval, magic and firearms supplements. In addition, there are rules for a medieval board game that allows you to lay out larger battles.
Pulp Avengers is a sourcebook for role playing in the 1930s and 1940s. It’s perfect for providing a realistic background for your games of the Pulp era.
Imaginality is a universal RPG where the action is resolved by playing a card from a hand of seven. This adds an additinal element of strategy, because payers get to decide when they REALLY need to succeed, and when they can afford to take a risk, or live with a lesser success.