Rusted Warfare is a good and cheap mobile game. No ads, otp, and it has LAN/WAN connections (not the most user friendly)

Rain World used to be a small game. Its rising in popularity now but is all around amazing. It doesn't offer the most guidance but is extremely rewarding for those who stick with it.

And a classic is Castle Crashers if that happens to be before your time or you never got the chance to play it.