Here are some of the online programming communities I participate in.
Here are the programming languages that I use the most.
ActionScript 3
C++11
C#
GameMaker - Standard edition is free
Java
JavaScript
Mathematica
MySQL
PHP
Python
R
Here are some of the IDEs that I use for those languages.
FlashDevelop - open source and free
NetBeans - open source and free
PyCharm - Community edition is open source and free
RStudio - open source and free
Visual Studio - Community (equivalent to Professional) edition is free for non-enterprise users