I wanted to organise my music while playing games, and I couldn't find a plugin that would let me do so. So I made one of my own.
Introducing HotkeyOrganiser. An arguably worse version of QuickTagger
by Al00X (since I didn't see that existed when I started searching).
This plugin allows you to set the genre of the currently playing song, add comments to it, and even send it to a specific playlist (something that QuickTagger doesn't do). It is very bare-bones since it was mainly developed for my personal use, but feel free to make recommendations here or even make a pull request on the GitHub
Check out the latest release here: https://github.com/LochTechMonster/MusicBee-HotkeyOrg/releases