Vertical tabs for firefox and lots of features. I use it myself in all my firefox profiles. It can be displayed as a sidebar or a popup. Which means you can use it in big windows and small windows.
https://addons.mozilla.org/en-US/firefox/addon/grasshopper-u...
Latest commit is on this little nim project to find text, similar to ripgrep
https://github.com/madprops/goldie
Last game is this thing where you get to see ants talk and react in different ways.
https://github.com/madprops/cromulant
Last big thing I made is this powerful python/tk client to chat with language models. Lots of features and my own markdown parser.