Drag for Gmail - Transform Gmail into organized To Do lists (like Trello)
Toby - Better Than Bookmarks
Palabra - Trello-style email sequences
Weava - Workspace to highlight, organize & collaborate on your research articles.
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Corrello - Dashboards for agile teams using Trello