I didn't make some of the themes here, this is just a list of themes I have downloaded or made for my own purposes. Creators of themes that weren't created by me are listed in the .css files.

To install, put the theme.css files that you want to use in your themes directory. The themes directory will be in AppData\Roaming\Vencord\themes if you're using Vencord, it is obviously different on BetterDiscord. Regardless of what client you're using though, there should be a button that just opens your themes directory when you click it somewhere in the settings.