Timings 3 - Timings - Track worktime on your Mac. Compatible with GrandTotal invoicing software.

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.

Chrono Plus - Chrono Plus is a convenient task manager and time tracking tool with a host of handy features

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.

Daily Time Tracking - Daily shows what you have been working on and for how long. It creates accurate timesheets by asking what you are doing, so no more timers or switching tasks. Use its data to submit your hours, create invoices or simply increase your productivity.

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