I remember all kinds of other protocols coming and going. Ymodem-g! Blazing fast. I never had issues with it but friends with worse modems/phone lines were always restarting their transfers.
Some SysOps would collect and support as many protocols as they could as sort of a form of bragging rights. Even with dozens, almost everyone used zmodem, or once in a while, BiModem if they wanted to chat during a transfer.
If I recall, Ymodem-G (as opposed to Ymodem) was basically an unchecksummed raw file dump with a little metadata header, so it was only usable on a connection without line noise. You could actually get undetected file corruption.
