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.
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Corrello - Dashboards for agile teams using Trello
Freezetab - A powerful alternative to bookmarks.