Do you have photos of any of the Pilot For Film pencils in lead diameters other than 0.5 mm? I’ve only ever seen them in 0.5 mm. Same for the grey H-56X (I have the grey H-565).
There is a post on Reddit by someone that shows HF-603/5/7 on the same picture. I’m not sure if 3/5/7 are the only 3 made or there is a HF-604/609 available as well.
https://www.instagram.com/p/Cf7YZ8fPsR6/?img_index=1
There is also a HF-609 which is hard to find. I also have Pilot plastic leads in most sizes including 0.3 mm plastic leads. As far as I know Pilot was the only source of 0.3 mm plastic leads. AFAIK there was no HF-604.
Yes, I occasionally see the HF-609. Not often. The set in my photo I got individually from various places: Brazil, Japan, and I think Spain. Had to use forwarding services, two were each around $75 - 100 usd plus shipping. One I got for $50 but that was just a rare and lucky find.