No one owns this list. Add whatever you feel appropriate
Added Beelinguapp and TangoRisto to the Android apps. (Also available for iOS as far as I know.) These are apps for reading and listening exercise, also good to train speaking by repeating the native audio. I use and enjoy them both, so I thought I should recommend them.
I do not know which category is because they have different types of content but I would recommend http://www.manythings.org/japanese/
There are street signs to read, random vocabulary generator to learn, JLPT compilations, Japanese learning resources compilation(resourception)
Added Charles Kelly’s Online Japanese Language Study Materials to Resource portals section per @Benedek’s suggestion
Expanded mobile apps section into device categories