Epic Pen - A windows tool for drawing over your desktop and applications
Sketch - Professional digital design for Mac.
gInk - An on-screen on-screen annotation software for Windows.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
ZoomIt - Presentation utility for zooming and drawing on the screen.
Affinity Designer - Professional creative software, exclusively for Mac.