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.

Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.

Clockify - Simple and free time tracker. Perfect for small and mid-sized businesses as well as freelancers. Unlimited projects and users, unlimited productivity. Get all the premium functionalities, completely free.

TimeStatement - A simple time & expense tracking software with powerful invoice & report generation, best Excel alternative / extension, timesheet...

Cattr - Cattr is a free open-source self-hosted time tracker with desktop clients for windows, mac, linux.

Punch - A simple, intuitive web publishing framework that will delight both designers and developers