List of installable tools

Copy and Paste dScan to share
Evepraisel for buying and selling all the things
Jabber - Chat about all the things
Mumble - Voice chat about all the things
TACO - Intel alerts
RIFT - Intel, Maps, Assets, Jabber, etc
GARPA - All you need in a mapping tool
pyfa - Used to save and view ship fittings
Eve-O Preview - Fly a lot of ships easily
ISBoxer - Fly a lot of ships easily. Be careful as some of the features of this tool are against CCP EULA
EveMon - Eve Character Monitoring

Mobile

Affordable Care App - Goonswarm Federation Reimbursement and You forum posting
External Service Authentication A page to manage your logins for Mumble, Jabber & Co
Fleet Dashboard Goonswarms fleet tracking tool
Goon Blog The Goonswarm's news page
GSF Auth The tool to add your characters and corps to the Goonswarm system and to apply for SIGs and squads
Imperium Skill Checker Gives you a good overview what doctrine you can fly how well and what skills you are lacking
Management Dashboard Your daily dose to see, how your corp is doing (as a CEO)
Region Commander 2 Timer tracker
Webway Scan tracking tool, especially useful to map wormholes