Gaming engines, 3D, and Stage 3D

As3isolib (v1.0) is an open-source ActionScript 3.0 Isometric Library developed to assist in creating isometrically projected content (such as games and graphics) targeted for the Flash player platform.

The Citrus Engine is a professional-grade Flash game engine built with diversity, speed, and scalability in mind. The Citrus Engine was built to allow designers and developers to quickly and easily create Flash games without worrying about architecture.

FlashPunk is a free ActionScript 3 library designed for developing 2D Flash games. It provides you with a fast, clean framework to prototype and develop your games in.

A revolution in Flash game production. An amazing new way for man to interface with machine. The beginning of a new tomorrow. Never before has the world witnessed such a collection of AS3 files.

The Smash Framework is an industrial strength, Open Source Flash game framework that is designed for a new generation of games. Created by the team who brought you PushButton Engine, the Smash Framework makes it easy to bring together great existing libraries and components for building games using Flash technology.

TheoWorlds Builder SDK v2 is a kit that will help you develop online virtual worlds much faster, without starting from scratch. At its core it contains our original Theo Isometric Engine™ that lets you create pseudo-3D maps, place on them objects and characters, and organize the interaction between them.

OpenSpace is a powerful framework for the Flash platform for rapid development of isometric multiplayer virtual worlds and MMO communities.

Alternativa3D is a 3D engine that allows developers to work with 3D graphics and physics in Adobe Flash.

Axel is an open-source Stage3D GPU accelerated 2D game library that makes flash game development as easy as possible.

EasyAGAL is an open source ActionScript library that simplifies coding assembly language shaders.  Advantages include:  Code completion and hinting, easier-to-read code, macro libraries (including all the blend modes in Photoshop, ready to use in your own shaders) and more.

Flare3D is a complete solution (tool and engine) to allow developers and designers to leverage 3D in Flash.

The FIVe3D initiative is an open source code for the conception of interactive vector-based 3D animations. 

Minko is a tool that enables the creation of rich and interactive 3D web applications. Relying on the Adobe Flash Platform, available on 97% of the computers connected to the Internet, Minko can deliver high quality and interactive 3D graphics in any website.

ND2D is a Stage 3D GPU accelerated 2D game engine made by nulldesign.

Sandy is a Flash 3D engine, available in 3 versions: AS2, AS3 and haXe.

APE (Actionscript Physics Engine) is a free AS3 open source 2D physics engine for use in Flash and Flex.

Box2DFlashAS3 is an open source port of Erin Catto's powerful c++ physics library Box2D.

The Box2D Flash Alchemy Port is a 2D physics engine for AS3, built on the C++ Box2D engine compiled with Adobe Alchemy.

The fisix engine is a verlet based physics engine for flash written in Actionscript 3.0.

Flave is a Flash-based, OOP verlet physics engine developed in AS3 and Flash.

JiglibFlash is a open source Actionscript 3D Physics Engine. It’s ported from the c++ open source physics engine jiglib.

Nape is a physics engine built in haXe using the caXe preprocessor and the caXe Std Library for targeting Flash Player 9, 10, and 10.1.

World Construction Kit is is a toolset / framework for rapidly developing physics-based games within Flash Professinonal.

WOW-Engine is a free AS3 open source physics engine capable of handling positions in a 3D environment.