Flow - Stop managing projects from your inbox.
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.
My Desk - A smart task manager for freelancers
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Corrello - Dashboards for agile teams using Trello
Fresboard - Notes, tasks & chat - Unified workspaces for projects