Isometric Game Art Pack - Extensive library of game art for indie devs
CThruView Transparent Image Viewer - CThruView is a free transparent image viewer that allows mouse clicks to go through the image.
Sketch This - Daily drawing challenges
LayerX - An intuitive app to display transparent images on screen.
IsometricSass - Make isometric 2D objects without Javascript
PixelPerfect - Allows developers to put a semi-transparent image overlay over the top of the developed HTML and...