I think the only floppy disk that I know of that I didn't use was the 7"? I think it was 7. The one that's larger than the 5.25" that was really common.
From there I've used or handled just about every type of digital storage. The 5.25" floppy disks are classic, but easily near the bottom of my list for favorites. They're down there with anything on tape (which is useful but always a hassle), and early USB drives when they used the cheapest solid state IC they could find and no matter what you did the IC was always painfully slow and there was nothing you could do about it because every manufacturer did that shit.
3.5" was rigid on the outside, floppy in the middle. Still a floppy diskette in my view.
Back when I was in school, I was working on the side on expanding an ERP system for a customer. Said customer got a stack of printouts from their main supplier each January: The new price list. They meticiously typed that 300+ pages list into their own ERP system, and then checked it for errors. This took the boss and his wife a good part of January and February. Every year.
So I told him that the main supplier already has that data in a computer, why does he not ask to get the price list on disk, and I see whether I can get them into the system via a software import. He called them, asked me back if "IBM Format" would be OK, and I said yes. Surprise: The supplier had an IBM mainframe and sent us an 8" floppy. Luckily, the boss knew the right people with the right equipment and got me a copy on 5.25" and in ASCII (the original was in EBCDIC).
It took me one day to figure out the format, write an importer, and run it to completion. Boss and wife were very happy.