TabSearcher by Gerald

This add-on source code was built on top of the TabSearch add-on.

Features
* Keyboard-accessible interface for tab management (with customizable shortcuts)
* Extensive options for configuration
* Can search bookmarks and history
* List and restore recently closed tabs
* Visual count of the number of tabs open in a window

You can always read the latest version of the changelog here

Shortcuts

All below except 'Toggle Extension' are customizable from the extension settings page. You can set up to two shortcuts for each command (except 'Toggle Extension')

Ctrl + Shift + F - Toggle extension (Windows/Linux)
Cmd + Shift + L - Toggle extension (macOS)
Ctrl + Backspace - Delete tab
Enter - Open selected tab or first in list if not selected
Up/Left - Select previous tab
Down/Right - Select next tab
Alt + R - Refresh tab
Alt + P - Pin tab
Ctrl + C - Copy Tab URL
Alt + Shift + D - Delete all duplicate tabs
Alt + M - Mute (only if tab is audible)

Privacy Policy
None of your browsing information is saved or accessed. Your browser's storage is only used to save your settings.

Known Issues
- If you see a shortcut that's set to the "Win" key it will not work, please disable it or set it to another binding
- Successive presses of the "Toggle Mute" command don't work. Switch to another tab then back before re-pressing toggling mute

The issues below are mainly Firefox issues:
- If the popup icon is hidden inside the overflow toolbar menu, the popup shortcut won't work.
- Input might not focus when the search popup is activated for certain users (Windows users mainly report this). Bugzilla Report. Fixed in FF60. Workaround for now is pressing tab after the popup opens (thanks recycler.fox for the suggestion)
- Popup activation shortcut: changing this is possible after FF60, still need to update the extension to support this

This extension is open source, see the repository here
Also check out the original source at: https://github.com/reblws/tab-search/