Dxtory - Tool to display FPS in video games, make screenshots, record videos.
Epic Pen - A windows tool for drawing over your desktop and applications
ConnectWise Control - ConnectWise Control is a mobile app that allows you to instantly connect with another system from anywhere with a connection to the internet. The software not only comes in a mobile app, but it has a desktop version as well for complete coverage.
gInk - An on-screen on-screen annotation software for Windows.
Nvidia ShadowPlay - ShadowPlay
OBS Studio - Free and open source software for video recording and live streaming for Mac, Windows and Linux.