Heya, and welcome to Azure's first Number Showcase! :D
Seenit is a number so massive that the picture I made for it (i'm bad at making those number things) was so big I couldn't upload it. I'll make a link to it sometime.
Graham Cracker is Graham Train, but with BIG FOOT replaced by Graham's Number.
For G = Googol, Rainbow can be represented by:
The function Rainbow(n) replaces G with n.