Sublime Text - Sublime Text is a sophisticated text editor for code, html and prose - any kind of text file. You'll love the slick user interface and extraordinary features. Fully customizable with macros, and syntax highlighting for most major languages.
JPEXS Free Flash Decompiler - JPEXS Free Flash Decompiler (FFDec) is an opensource Shockwave Flash (SWF) decompiler.
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
Flash Decompiler Trillix - SWF Decompiler Trillix allows you to decompile SWF (Flash), convert SWF to FLA, extract SWF elements and edit SWF file. Supports AS 3.0, Flash CS6 & CC and Flex.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
SWF Picture Extractor - Free Flash Player for Mac which can be used both as SWF Player and FLV Player for Mac to playback Flash movies with plenty of useful features.