Slackbox - Spotify playlist collaboration through Slack
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
RightGIF - Less noise, better GIFs. A better /giphy for Slack.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Remixatron - Infinite Jukebox on the command line in Python.
LightShot - The fastest way to take a customizable screenshot.