Free Flash Effect Generator!

Adobe Animate, previously Adobe Flash Professional, is an authoring environment (IDE) that can produce interactive solutions for running inside web browsers or for the desktop.

FlashDevelop is a free and open source (MIT license) code editor for Actionscript (2 and 3), Flex (MXML) and HaXe.

Adobe Flash Builder 4 (formerly Adobe Flex Builder) software is designed to help software developers rapidly develop cross-platform rich Internet applications (RIAs) and content using the open source Flex framework. It includes support for intelligent coding, debugging, and visual design and features powerful testing tools that speed up development and lead to higher performing applications.

MiniBuilder is a very lightweight Flash builder, created for developing programs written in ActionScript 3. It's written in ActionScript itself.

AXDT is a plugin for Eclipse IDE that makes it possible to write MXML and AS3 with code support.You can also compile and build your flex application under same.

FDT is a powerful Flash/Flex development environment for ActionScript, MXML and haXe. FDT enhances your workflow while increasing your productivity.