Various wheels from Rocket League. These are a bit outdated and do not include most of the wheels that come from crates. Getting the game files takes a lot of time and I have not done it in a while. Some export weird and may not be printable. Sorry, I haven't tried most of them but I didn't see many Rocket League wheels on Thingiverse so I figured it was better than nothing.

Edit:
I added wheel_cutout and wheel_addon so wheels can snap in to the axles for the cars in my profile (or any cars with axles big enough). Scale the car and wheels to whatever you want, then merge the wheel_addon to the back (inside) of your wheels and use the wheel_cutout to delete space in the axles. If done correctly, the wheels should simply snap in to the car allowing them to rotate freely and potentially swap out wheels. It takes a little bit of wearing-in for it to roll smoothly, and I used lithium grease to make it smoother and to prevent squeaking.