Popclip - PopClip appears when you select text with your mouse on your Mac.
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.
Pantherbar - Pantherbar is a tool that lets you perform instant actions when selecting text.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Universal Tip - Programmable tooltip that can be used with every macOS app
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.