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.

Pocket - When you find something you want to view later, put it in Pocket.

Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.

Raindrop.io - All your articles, photos, video & content from web & apps in one place.

Corrello - Dashboards for agile teams using Trello

Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.