I purchased a ream of HP Premium32 printer paper in 2020 and found a couple of sites that offer ruled paper templates. I use the templates to print my own writing paper on a black and white laser printer.

It isn't Clairefontaine, but it is very nice to write on. I highly recommend it.

I'm not sure that I understand your request (alternative as compared to...?), but I have used isbn.nu for many, many years now.