Typically considered something that will protect your tank, a paintball tank cover is more designed to help provide adequate grip when you shoulder your marker. These tank covers can certainly add a little bit of protection to your tank as well as some do cover most of it, they also can help you add a little bit of style to your setup. There are multiple different types of tank covers, but the most common ones are either tank butts which just cover the rear end of the tank, or full coverage tank covers which will cover all or most of the tank.
Paintball tank covers are going to be size specific, so be certain as you are looking for one for your tank that you know what size you need. Some companies will have individual ones for each size of tank, others will have a small / medium / large size system for them, it all depends which ones you are looking for. Typically, tank butt style covers will work on all 4500psi tanks from 48ci to 80ci depending on the manufacturer and individual tanks.
Companies like Exalt, HK Army, Dye, Virtue, and many more or always designing new paintball tank covers, and once they are released, they will all be added right here!