Here are some of the products that I use to make my digis and colorings...
I use copic perfect coloring paper for most of my coloring.
This paper is very thick, and lets you blend so easily with copics... you can build up a lot of interesting color with this paper, and sometimes even fix mistakes as if they were never there!
I also use xpress-it blending paper... this paper is similar to the copic perfect coloring paper. Again, it is very thick and allows blending.
The links on this page contain an affiliate id, this will not charge you anything, but if you click them to make a purchase to Amazon, they give me a small commission, which helps keep me in pencils :)