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.
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Slack - A messaging app for teams who see through the Earth!
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.