LF paper recos for fountain pen users

Hi! I run a humble art supply sh0p in our community and we've been meeting a lot of fountainpen users LF paper (which is the first thing they run out of daw). Our advocacy is to for arts and creativity to be accessible and are looking into trying to carry some.

If it's alright, please help enlighten me regarding paper brands, sizes and if lined/gridded/blank paper would be generally best? I write a lot also but I haven't used my fountainpen in ages and didn't realize it's a whole hobby until now.

(My background is more on painting so I have no idea what's best for these ink users🤩)

Thanks in advance for any leads! 🩷