Taiga - Project management platform for agile developers & designers
Hygger - Hygger - is an Agile project management tool with built-in prioritization.
Scrumwise - The most intuitive Scrum tool you've ever tried.
TargetProcess - Agile Project Management Web Application
Leantime - Lean project management for startups & small teams
Planning Poker - Open source implementation of planning poker game (collaborative online estimation/voting tool).