Renaissance Art has a huge variety of types and colors of leathers to choose from for their Moleskine and Custom leather covers.
There is a thicker, more rustic leather that is available in black or brown, and a thinner sleeker leather that comes in loads of colors. All of these are shown below:
Here are The Browns. The colors are, starting top left, Distressed Rustic Brown, Rustic Brown, British Tan. Bottom row at left is Flight Jacket, and bottom right is Molasses (which I reviewed a cover made from, click here to see).
Here are what I call The Deeps. Top left is Black and top right is Rustic Black, which is thicker.
which I reviewed in a custom cover here) and Wintergreen.
Below are the backs of these samples with the name labels visible.
Here are what I call The Brights. At the top are Cranberry and Ocean Blue.
Below are the backs:
I didn't know this before, but Ren Art also has a variety of papers used in their leather journals, sketchbooks and photo albums. Below are photos of the paper selection to choose from. At the top left is Frankfurt White, which is 120 gsm. Top right is Zerkall Book white/ smooth which is 145 gsm.
All of these papers are designed to take inks well. I don't use fountain pens, but you can click here to see O-kami's review of these papers with ink tests.
You can buy these samples on the Renaissance Art website to help you decide how to customize your book. The cost of the samples is credited to your account for a future purchase so in the end they don't cost you anything.
Many thanks to Ren Art for sending me these samples to review!