Planning Poker by Standuply - Asynchronous planning poker via Slack task-based surveys
Planning Poker - Open source implementation of planning poker game (collaborative online estimation/voting tool).
Sprint Poker by Parabol - Remotely bring planning poker to life
Firepoker - Agile Planning Poker powered by Firebase and AngularJS
Planning Poker for teams - Estimation for agile teams
Taiga - Project management platform for agile developers & designers