Looking through this forum I am slightly surprised that nobody has mentioned the venerable English watermarked paper Basildon Bond. When I was sorting out our writing bureau the other evening, I found a pad of A4 size BB in one of the drawers. Judging by the packaging it was 1980s vintage; it had been bought by my wife, probably when she was a student (we met at university).
I had a go writing on a couple of pieces and found it was quite pleasant to write on. Not Earth-shattering but quite pleasant with my Parker Vector. The pad comes with a writing template and a sheet of blotting paper as well! A nice surprise.
Best wishes
Bruce