ColorSnapper - The missing color picker for Mac.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Sip - A better way to collect, organize & share your colors.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
ColorSlurp - Pick, edit, save, and copy colors. The best color picker in the universe!
LightShot - The fastest way to take a customizable screenshot.