Happy Tools by Automattic - A scheduling tool built for distributed teams
WhatRuns - Extension that helps you identify technologies used on any website at the click of a button.
Talllly - A team to-do list that keeps score.
Checklist Generator - Create checklists for free and host them wherever you want.
listshare - Create beautiful, interactive lists to share with the world.
Visual Designer Checklist - Workflow checklist tool for designers working within a team