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

iStat Menus - "An advanced Mac system monitor for your menubar."

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.

iStatistica Pro - System monitor. Reinvented. 💻 🖥

Pomodone - Pomodone is the easiest way to track your workflow using Pomodoro technique, on top of your current task management service.

Stats - Simple macOS system monitor in your menu bar.