ND2D
A Flash Molehill (Stage3D) GPU accelerated 2D game engine
...It includes display tree constructs, sprite sheets, particle systems, cameras, post-processing etc., made to simplify building high-performance 2D content in Flash. ND2D was built to make an ease use of hardware accelerated 2D content in the Flashplayer. The aim is to keep things simple and reintroduce familiar concepts. ND2D has a displaylist and quite the same methods to modify sprites as you are used to, but a few things are different. There are optimizations in ND2D, that enable you to display thousands of sprites at a high framerate. Have a look at the examples for the Sprite2DCloud or Sprite2DBatch and in the Wiki.