Here are a few game items of mine. Most of these are from when I originally tried making games in my youth.
Open World Space Trader w/ 2D Shmup Graphics + Combat - I was thinking a crossover between Elite, a bullet hell shooter, and Asteroids. In particular, I want the Asteroids style control to allow for strafing type shots.
2D Tactical RTS based on Aliens - This is a tactical RTS based on the Aliens movie. The idea is you have a squad of colonial marines and have to investigate and clear out infested colonies. A big game mechanic involves line-of-sight; you can only see what your squad can see. Since the levels are mostly tight interiors with lots of corridors, you need to maneuver your squad to maximize your situational awareness and avoid being taken by surprise. Back in the day I actually built an engine for this, but never got past the basic prototype.
2D Street Hockey Game - I played a lot of street hockey when I was younger and wanted to make a game based on that. It would be 2-on-2 with a single goalie/net. Teams would switch between offense and defense based on whoever was carrying the ball into the offensive zone. One feature would be the ability to use a tennis ball versus an orange ball, and have different physics result. Again, built a basic prototype complete with ball physics, but never got around to programming a goalie...
Text-based Hacking Game - You know those scenes in movies and TV where people are hacking or counter-hacking and they are madly typing away like crazy? I always thought that would make for an interesting game mechanic. Most of the game would just be standard text commands. But every once in awhile there would be a timed hacking scenario, forcing the player to type very quickly. And I figure there might even be a way to work in typing in random gibberish as quickly as possible (i.e. flooding the opponent with nonsensical data to slow down an attack or something).
Anyway, these are some of my ideas. Not all that original, especially these days, but stuff I dabbled with before and may again...