Heres an item that checks all the boxes.

Yamamoto Paper: Paper Tasting - Egg Shell Vol.3

A paper pack designed for enjoying the writing feel and paper quality. It includes three types and sizes of paper. You can try out the papers and find your preferred one. "Paper tasting" allows you to enjoy the "tasting" of paper.

With an included guide, you can enjoy specialized knowledge about paper that isn't typically known in daily life, such as how to indicate and calculate paper thickness, paper manufacturing methods, or the origins of paper dimensions.

B7 size: Slight
A6 size: Monte Lukia
B6 size: Soliste

Heres a choice that fits any budget, any lifestyle.