I recently launched my 7th Kickstarter campaign to produce pads of Dungeon Mapping Paper. The project has already passed its initial goal and is very close to reaching its first stretch goal. The pads will be litho-printed with a light grey, 7mm grid. If the stretch goal is met than the sheets will be upgraded to heavier paper and double-sided printing (the reverse side of the sheets will have a 3.5mm grid). Here's a link the the project page:
https://www.kickstarter.com/projects/1730454032/a4-and-a5-dungeon-mapping-pads
Samples of the pads
Close-up of a litho-printed 7mm grid
Sample map drawn on an A5 sheet