I always make my own, using https://color.firefox.com/
Firefox
A community for discussion about Mozilla Firefox.
Started using EdgyArc-fr the other day and like it quite a lot.
Woahh this one looks super neat! Defo gonna give this a try ๐
I use the Safari theme that comes with WhiteSur.
I like that it all looks well together, has a nice seemingly good feel to it!
You should check out Bonjourr too, it would go well with this!
I like this one because it takes advantage of the animation support: https://addons.mozilla.org/en-US/firefox/addon/nicothin-space/
I'm doing a gtk thing
If you use GNOME https://github.com/rafaelmardojai/firefox-gnome-theme blends perfectly with libadwaita.
I'm a KDE kinda guy, but nice of someone to make a theme that blends in better!
Ever since the old theming enging was retired I have stopped changing the theme.
Back in the old days I used Noia 2 Extreme:
https://www.deviantart.com/kasteo/art/Noia-2-0-eXtreme-For-Firefox-4266778
Well that's certainly old school! ;D
When Firefox started copying Chrome with Australis, I moved to Pale Moon as I just could not stand the terrible design.
Then when the Photon redesign came out it was actually looking good so I switched back to Firefox
Personally been using TokyoNight theme for a good while now, https://addons.mozilla.org/en-GB/firefox/addon/tokyo-night-milav/
With the Adaptive Tab add-on, the theme changes to match the colour of the site I am on. Like in Vivaldi. That's my favourite.
Hololive Hoshimachi Suisei (Dark) https://addons.mozilla.org/en-US/firefox/addon/hololive-hoshimachi-suisei
Dark [Developer] theme.