My favorites were the old Agfa cartridges. As late as the 1970s Ilford sold film on spools without the rest of the cartridge and wrapped in foil. You would go into the darkroom or use a changing bag to take off the foil and insert the spool with the film into a used cartridge. I used to tape the end of the old black plastic screw cap cartridges so they wouldn't open up by themselves. The most frustrating cartridge was the Kodak Snap Cap. It was liable to pop open at any time with no warning. I need to try the reloadable Nikon cartridges in one of my F2 bodies. At some point recently I was on the Freestyle website when they were still selling the relabeled Tri-X in bulk rolls. The spooled film was almost the same price per roll as the bulk film so I bought the spooled film instead.