Quickly and easily switch between popular user-agent strings.
Create a QR code of the selected text, current url or hyperlink. Also possible to create a QR Code from free text within Firefox. Now with UTF8 support.
SmartProxy will automatically enable/disable proxy for the sites you visit, based on customizable patterns.
An easy-to-use font inspector to get CSS styles of the selected element
Does everything for an HTML table: Copy (table/row/column/cell), Sort (multi-column), Search (regex, range operations ...), Filter, Chart, Statistics, Rearrange, Combine/Compare. To use: Right click in a real HTML table for the "tabletools2" option.
'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions. Beta builds on versions page!
Add-on to display GitHub code in tree format
The "NewScrollbars"-extension replaces default scrollbars of Firefox and Thunderbird with colorized ones (partly) known from "Noia themes". [ not compatible with Firefox / Thunderbird 57+ ]
manage, edit, manipulate, plot and save one or multiple SQLite databases simultaneously
Redesign the web with Stylus, a user styles manager. Stylus allows you to easily install themes and skins for many popular sites.
Simulate the use of a series of proxy changing at each new connection.
It is a universal night mode for the entire Internet. It uses a special algorithm to automatically change the colors of the websites you visit into dark mode so that you can browse without straining your eyes, especially at night.