There are quite good quality paper notebooks in Europe, these are the ones I know:
Rhodia/Clairefontaine/Oxford - French, with one of the best quality paper I know. Not very expensive, Rhodia is the most expensive one, and Oxford the cheapest, often used at schools.
Miquelrius - Spanish, quite good paper, quite good price
Moleskine - Italian, the most expensive of the lot, and very famous, its paper quality is not good if you use fountain pens
Leuchtturm - German, similar to Moleskine and in several product lines, quite good quality paper.
Dingbats - British, very good paper, and they give a percentage of what they earn to projects related to nature protection. A bit cheaper than Moleskine and Leuchturm
Online - Another german brand, decent paper. In the Rhodia/clairefontaine price range
Do you know any other notebook brands from Europe? would like to try some more (bit crazy about stationery)
Leuchtturm is my go to notebook. S tier.
I am trying a flexible B6, and this is a size I really like and will stick with. Had to go for one with dots instead of grid, however. I also wish they made the grid in nice colours as the dots and lines, but black will do.