Epic Pen - A windows tool for drawing over your desktop and applications
CThruView Transparent Image Viewer - CThruView is a free transparent image viewer that allows mouse clicks to go through the image.
gInk - An on-screen on-screen annotation software for Windows.
PixelPerfect - Allows developers to put a semi-transparent image overlay over the top of the developed HTML and...
Gromit-MPX - Create annotations by directly drawing on your screen.
Osiva - Osiva" is an acronym that stands for "Overly Simple Image Viewing