The Digital Library for Miis
The Mii Library is a site documenting every single Mii to have ever been used in an official capacity, by HEYimHeroic (you also may know me as Wii Facts Plus) using Google Sites. Every Mii will have images of their face and fully body, and a QR code image to be scanned into Mii Maker or other Mii QR code-supporting app. There are currently an estimated amount of around 3,000 Miis total that qualify to be added to the site, and 248 Miis are on the site right now.
Along with those three photos mentioned, every Mii's page will have detailed information about the Mii, including the games the Mii appears in, where this Mii is used in the game, and any hidden information found in the Mii data file. Additionally, if a Mii originates from the Wii or the Switch, step-by-step instructions on how to recreate the Mii will be available, due to those platforms not supporting QR codes.
Click a system to get started on viewing Miis from that system, or click the button below it, "All Miis", to view a list of all of the Miis.