Tabhunter by Eric Promislow

This extension lets Firefox users easily juggle dozens of tabs at a time. Enter a search string (actually a standard JavaScript regex), highlight the URL you want to bring up, and press return or double-click it. Tabhunter will even bring up minimized windows containing the target tab.

Post-Obama changes[*] in Firefox extensions internals have changed the way Tabhunter behaves. It currently can't run as a standalone window, but shows up as a popup anchored in the main toolbar. You can get it to popup by pressing the telescope-like icon in the toolbar. Default shortcuts are Ctrl-Shift-T on OSX, Ctrl-5 on Linux, and Ctrl-Shift-S on Windows. These might be overridden by newer versions of Firefox or other extensions, but with newer versions of Firefox you can change this shortcut in the Preferences Panel, accessible on the Add-ons page or via the "More..." button on the Tabhunter panel: click on the "Startup Key Sequence" textbox and type your new desired shortcut. If your version isn't new enough, you shouldn't see that textbox.

Please be sure to tell your friends that Tabhunter is now available in that other browser that anagrams to "ochre logo gem". Whatever, it still quickly helps you unearth that tab you know you brought up a week ago and haven't yet closed.

The one real new feature lets you select only tabs that are playing some audio. If you accidentally invoke "Reload All Tabs" and a bunch of tabs start playing music, you can now click on the "Audio Only" button and isolate them.

Also, Tabhunter finally supports changing the font size. See the prefs.

The "More" section has more functionality:
* manipulate the "Discarded" status of tabs, or avoid showing any discarded tabs
* move tabs to selected window
* bookmark selected tabs (firefox only)

Apart from fetching favicons associated with tabs that are currently loaded in your browser, Tabhunter does not transmit any information to other computers. It saves some innocuous usage-related preference information in the browser's local preference cache, and if other users have access to it, either use a better password or speak to the person who set up your machine. If you're unsure about this, find yourself another tab hunter, or go watch some old 1960s beach movies.

[*] I'm sure this is coincidental.