For taking notes, sketches and generally just having paper with me that works well with my fountain pens, I’ve been using Fabriano’s EcoQua notebooks.
The dot-ruled, staple bound sheets of 85gsm off-white paper work fantastically with my my favorite pens and inks. There is nearly zero bleed through or feathering, and ink dries fast. My favorite Noodler’s bulletproof black and red-black are both bold and bright, though the red-black becomes distinctively more red.
I really the dot-ruled paper. It is a more subtle version of quad-ruled graphing paper, but helps me sketch and draw out ideas.
There is a lot of marketing hullabaloo over the environmentally friendly nature of these notebooks. I find this ironic, as we start with killing a tree, but appreciate it regardless.
Ecoqua Dot Notebook 5.8X8.25 Navy via Amazon