Extremely rare. I never encountered one, and I had a lot of niche stuff in the 90s.
1.44MB was the effective capacity of floppies until they died out. There was stuff like VGACopy that could format them with higher capacity (since floppy controller access was fairly low level), but it was an uncommon thing among tinkerers, the disks themselves were not marketed for more than 1.44MB, and I doubt they were tested above their nominal capacity (and even at that they were not exactly known as super reliably).
1.44MB was the effective capacity of floppies until they died out. There was stuff like VGACopy that could format them with higher capacity (since floppy controller access was fairly low level), but it was an uncommon thing among tinkerers, the disks themselves were not marketed for more than 1.44MB, and I doubt they were tested above their nominal capacity (and even at that they were not exactly known as super reliably).