Finding direct downloads for "highly compressed" Wii games (ISOs) is legally problematic due to copyright, but there is significant academic and technical interest in the compression techniques used to reduce the file sizes of Wii and GameCube games.
For Dolphin emulator, .RVZ is the king of highly compressed Wii games. It can shrink a 4.37 GB game down to 1.2 GB without any loss in gameplay or audio quality. For real Wiis using USB Loader GX, .WBFS remains the standard. highly compressed wii games