tool category  
  animation and video   
Wick Editor
free and open source tool for creating animations, games and multi media projects.   
FlipAnim
free browser based tool for creating simpel digital flipbooks
Mutsuacen
free browser based tool for experimental animations
free and open source video editor
Shotcut
free and open source video editor
Open Shot
free and open source video editor
Stop Motion Studio
Mobile App (free trial) for stop-motion animation with onion skinning and timeline editing
Tagtool
Free iPad App (in app €) for collaborative live painting. Connected with a projector you can paint with light everywhere you want.