Hey Coders/Programmers, What is in your toolbox?

Looking for shares about tools/extensions/blogs/forums that helping you when doing as a coder/programmer.

Here are one or two I have come across so far and examples:

Applications - Notepad++, Dreamweaver
Chrome/Firefox Extensions - Measureit, Alexa ranking, SEOquake
Learning Resources - Lynda, Udemy
We design - Css foundation, Bootstrap

Will hopefully be a good resource for new tools to try for coders and newbies alike.

Please list your favourites