Steam FPS game recommendation

It all depends how much money do you have and if you want single player or multiplayer.
If you want singleplayer take a look at new wolfenstein and new doom. If you look for a good multiplayer there are only two recommendation that can give you. TF2 and Quake Champions.

Quake is new so doesn't have too many players but it will grow with time.
TF2 is a game that will get you addicted to the point that you will be spending a lot of time and money (BUY MORE HATS!!!) but try to avoid in-game store. Valve is rly trying to scam people. You can get those items almost for free. I can give you links to a few sites that might be useful in future. Just PM me