Authors of the textures

Schueler-Design (blue one) (I edited it adding 20% brightness on Power Point)
1200219 (yellow one)
FixiPixi_deluxe (violet in the Halloween version)
John Harvey (orange in the Halloween version)

I found the textures searching on google for textures with free use, then I checked if they could be modificated and they can, but I felt like the creators need some credit for their work.