I noticed that this section was missing my favorite tool for reversing APKS: Virtuous Ten Studio ;)

This program is a very quick, efficient, and easy way to reverse engineer and modify APK files. With its sleek and intuitive design, Virtuous Ten Studio can assist and streamline your reverse engineering efforts. Best of all, the program is completely free! You can optionally donate to help the developers of this program, but it is not required and you will still have full access to all of the features. I recommend that you check this out if you are running Windows and you need to reverse an APK. You won't regret it!

Here's a screenshot of the program's welcome page so can see the GUI: (Warning: large image)

Oh wow, is this open sourced? Also the URL you added isn't working.

Oh wow, is this open sourced? Also the URL you added isn't working.

Whoops thanks for pointing that out.

Unfortunately, it's closed source :/ I wish it was open source, but no such luck.

It is a .net application. Just use .net reflector, ilspy, dnspy, or your favorite .net decompiler to look at the source code.