Epic Pen - A windows tool for drawing over your desktop and applications
gInk - An on-screen on-screen annotation software for Windows.
ZoomIt - Presentation utility for zooming and drawing on the screen.
OBS Studio - Free and open source software for video recording and live streaming for Mac, Windows and Linux.
Gromit-MPX - Create annotations by directly drawing on your screen.
Ardesia - Ardesia is an usefull software for use your desktop as a Sketchpad.