Mozilla plugins 

Firefox:

  • Xmarks
  • NoScript
  • WorldIP
  • All-in-One Gestures
  • CypherFox
  • Firebug
  • FoxyProxy Standard
  • IPvFox
  • lori (Life-of-request info)
  • Page Speed
  • ReloadEvery
  • User Agent Overrider
  • Yslow

Thunderbird:

  • Display mail user agent
  • Lightning
  • Provider for Google Calendar