Wii Shop Channel closed 2019. No official downloads possible. For homebrew/backups:
apps/ (Homebrew Channel apps), wad/ (WAD manager), private/ (save exploits).Downloading Wii ISOs/WADs you don't own is piracy. Only install backups of games you physically own. Brick risk is real with bad WADs (banner bricks, semi-bricks). Use Priiloader + BootMii (boot2 if pre-2008) for recovery.
For legitimate play: Original discs + USB Loader GX (ripped to USB HDD) is safest.