Fountain Pens

My favorite notebook is the JetPens Kanso Noto. They have 160 sheets (320 pages) of Tomoe River paper with a 5mm dot grid. Tomoe River paper is a premium fountain pen friendly paper that should solve your feathering problems.

https://www.jetpens.com/JetPens-Tomoe-River-52-gsm-Kanso-Noto-Notebook-A5-Dot-Grid-Black/pd/29704

JetPens offers free shipping in the US for order of $35 or more. I don't know what options are available outside of the US.

The notebook is currently out of stock. I expect more to be back soon. Tomoe River paper was sold from one paper company to another. I think JetPens just cleared out their stock with paper from the original company and I anticipate they'll bring the notebook back soon with paper from the new company (Sanzen). In the past, the notebooks sold for $19.50, which is a great price for a premium paper notebook (seriously, I think only the Nanami Seven Seas notebooks have a better price per page for premium paper) . However, to keep the price low, the notebook doesn't have bells and whistles like an elastic closure or page marker ribbons.

I use a Hobonichi techo planner and grid notebooks. I also use Midori grid notebooks. No feathering on both, not too glossy so my nib doesn't "skate" on top. I like Rhodia pads (some of the notebooks feather). Clairfontaine is lovely smooth paper but my pens usually "skate" on it and I can't control my handwriting on it, but YMMV.

Hobonichi Techo is always good, but more oriented towards keeping a diary and a little expensive (though you get what you pay for).

Midori MD pads with one of their covers work well and aren't too expensive. Available in A5 and A6 if I recall. Otherwise as already mentioned I like the 90gsm Rhodia or Clairefontaine notebooks. The 80gsm Rhodia paper (found in a lot of their pads) always feels like the backside of the paper has less coating on it and not as enjoyable.

I like my Hobonichi Techo planner. The paper is thin, so it ghosts a bit, but it doesn’t bleed. I think they also make plain journals, and it’s not uncommon for Hobonichi fans to buy an extra planner to use as a journal.

@kalanggam As others have said, the Hobonichi's are great with fountain pens, or if it's more of a pure journal you're after the Luechtturm1917 Bullet Journal performs excellently.