ActivityWatch - Log what you do on your computer. Simple (yet powerful), extensible, no third parties.
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.
WakaTime - Analytics for programmers using open-source text editor plugins.
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.
TimeCamp - Simple and robust time tracking app to help you stay on the same page with your team while working from home.
Cattr - Cattr is a free open-source self-hosted time tracker with desktop clients for windows, mac, linux.