Used to be a huge fan of an fps called A.V.A. Stopped playing it after it became pay to play. You can try it if you like but I haven't it played it since last year...
Now I play League of Legends a lot. It's a great game and it's free. I'm sure you've heard of it before 😉
If you want to practice your aim for fps I suggest to look into a game called osu! If you're an anime fan there's tons of songs to choose from, and even if you're not there are still regular songs which you can play. It really helps with hand-eye coordination.