Add-ons

ChatZilla by Gijs Kruitbosch, Robert Ginda, others

A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.

Collector's Note a simple IRC client. #wikipedia-en and #wikipedia-en-help, among others on the freenode network, are very useful places to idle. Ops or other powerusers should adopt mIRC or similar though.

Wikipedia (SSL) by SSL Search Bar

Wikipedia is an openly-editable, free content internet encyclopedia. This search bar add-on utilizes SSL to protect searches between You and Wikipedia.

Collector's Note Now obsolete. I recommend HTTPS Everywhere, which will force Wikipedia (and just about every other website by default) to secure. Get it at https://www.eff.org/https-everywhere

Wikimedia Commons by openstrings

Search for files in Wikimedia Commons with one click.

Simple English Wikipedia by openstrings

search the Simple English Wikipedia with one click: an easy-to-read alternative to the English Wikipedia.

Collector's Note From the POV of a simplewiki contributor, this is obviously useful to me- but it's also a good opportunity for enwiki or other language Wikipedians to give their knowledge to a project that doesn't know it all yet, or just to find an easier-to-read alternative :)