Maps

Dotlan Maps
Daily Sov Maps

Education/Reference

EVE University Wiki
DaOpa's EVE Info Database
EVE Survival
Chruker's EVE Reference

Market

EVE Marketer

Wormhole

Anoik.is Wormhole Reference
Pathfinder Wormhole Mapper
Tripwire Wormhole Mapper
EVE Scout
Siggy

Kill Tracking

zKillboard

Player Services

Red Frog Delivery Service

Fitting Tools

Pyfa
EVE Workbench

Developer

Official EVE API
zKillboard Docs