Epic Pen - A windows tool for drawing over your desktop and applications

Teampaper Snap - Take a snapshot, highlight key areas and share feedback

Gromit-MPX - Create annotations by directly drawing on your screen.

ppInk - a fork from gInk, with extra features (shape drawings, text,...)

Pylote - To draw on the screen and to handle the instruments of geometry there.

Zapsnap - Temporary peer to peer screenshot sharing in your browser