PlanITpoker - PlanITpoker is a cool on-line planning poker app that helps Agile project teams estimate projects easily.
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Firepoker - Agile Planning Poker powered by Firebase and AngularJS
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Planning Poker - Open source implementation of planning poker game (collaborative online estimation/voting tool).
Slack - A messaging app for teams who see through the Earth!