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.
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Qbserve - Freelance time tracking, invoicing, and productivity improvement
Paymo - Paymo is a modern and intuitive work management solution for small businesses around the world.
TimeCamp - Simple and robust time tracking app to help you stay on the same page with your team while working from home.