chitchat - Chat Room with Selfies and Pagers (yes, pagers!)
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Chalk - Chalk is a calculator that tries to do right what others do wrong.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Twist - Check fewer notifications, do more meaningful work. Twist is the team communication app for calmer, more organized, and more productive teamwork.
LightShot - The fastest way to take a customizable screenshot.