You need to give a little more information. B5 size? A4 size? How many sheets is "thick"? In Japan you can also specify the line height.
Here's a 100 page B5 notebook with 6mm lines, and the same with 7mm lines.
Here's an A4 size with 200 pages and thicker 8mm lines. Pricey though, probably because most Japanese seem to prefer smaller B5 notebooks.
I didn't see anything on Amazon with more than 200 pages but I'm not someone who buys notebooks. Hate paper in fact!
I hear you about the non spiral bound condition.. Here are some non spiral bound notebooks that I like:
A5:
http://www.midori-japan.co.jp/md/en/products/mdnote/ (I use Midori A5 grid, it's available on amazon)
Clairefontaine A5
Rhodia Webnotebook A5
B5:
Apica premium (will be more expensive)
Kokuyo Campus notebook: https://www.amazon.ca/Kokuyo-Campus-Notebook-Semi-Sheets/dp/B0012ONGHM/ref=sr_1_2?ie=UTF8&qid=1528065477&sr=8-2&keywords=kokuyo+campus+notebook+100+sheets
Life noble notebook
Baron fig
These are all beautiful.. there are more options but these are off the top of my head.
P.S. I also like the muji B5's you mentioned. They're 1.50 each so I don't mind that they only have ~30 sheets in them!
I bought a blue Campus notebook at a stationery store for $5 and wrote the title myself, for my brother who's going to cosplay Deku.
Amazon: Kokuyo Campus Notebook - https://www.amazon.com/dp/B0012ONGHM/ref=cm_sw_r_cp_api_i_.c2vBbVD41GCH