Like Brosj said, really sponge filters work for any tank size.
For smaller tanks, many just use a sponge filter or a smaller hang on the back. Some brands include Aqueon, Aquaclear, Fluval, Eheim (used to have smaller filters).
For medium tanks, mostly recommend hang on the back or canister filters. Some brands include Aqueon, Top Fin (for canister filter), Eheim, Aquaclear, SunSun, Marineland.
For big tanks, mostly recommend canister filters or sumps. Some brands include Eheim, SunSun, Marineland, Fluval, Penn-Plax, API.