Here is a list of communities that are related to the Wii.
BitBuilt - BitBuilt is a website for console modders and general electronic hobbyists alike. Founded in 2016, BitBuilt was brought to life by portablizer Noah, BoFoSho, and renowned console portablizing veteran ShockSlayer.
GBAtemp Forum - Wii Hacking - Talk about Wii hacking attempts and softmods!
Homebrew General - Homebrewing Community - WiiU Content
Horizon - Discord - Horizon is a New Super Mario Bros. Wii modding community
Kitty Corp Meow Mix Forums - A Brawl Modding Community
Nintendo Hacks 2.0 - Discord - A Nintendo Hacking Community
Nintendo Homebrew - Discord - A Nintendo Homebrewing Community
RiiConnect24 - RiiConnect24 brings back WiiConnect24, pushing content to your Wii.
RiiConnect24 - Discord - RiiConnect24 discord server.
Romhacking.net - A Rom Hacking Community
Smash Bros Legacy - Discord - A Smash Brothers Legacy Discord.
Wii-Homebrew.com Board - Everything about Homebrew, Tweaks and more for Wii, Wii U, DS, DSi, 2DS and 3DS
Wiibrew Forums - Homebrew development and experimentation on the Nintendo Wii platform
WiiBrew Wiki - a wiki dedicated to homebrew on the Nintendo Wii.
WiiDatabase (German) - Aktuelle News rund um Nintendo-Homebrew
Wiidewii.com - Support Forums for WiiCrazys software - Wii oyun, chip, usb loader, crap
Wii Hacking House - Discord - A Wii focuses hacking community.
Wii Mini Hacking - Discord - A community focused on the Wii Mini - home of the Bluebomb