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.
Sage HR - Sage HR is a one-stop shop for your HR management needs. Your HR - simplified!
GoodGantt - The best Gantt chart for Trello®
Calamari - Calamari helps organizations, companies, and enterprises to manage their human resources in an easy and compliant way by delivering modern and easy-to-use time tracking and attendance management tools.
Paws for Trello - The best way to use Trello on your desktop
Absence - Employee vacation tracking system