A list of KH related Tumblrs:
http://khdiaries.tumblr.com/ (This one's cute)
http://beyond-theisland.tumblr.com/ (Oh geez...this one says some interesting things about Saix and Axel before Org13),
“From where I stood, the only thing you drew was a big L on your forehead, for Loser…Lame…Laughable.”
— Isa, Birth by Sleep
Geez, there are quite a few of them on Tumblr. I bet this is only scratching the surface. Lots of great fanart/pics on those blogs!