LGR has a video about Danmere Backup system which used your home VCR for backups. It apparently could store up to 4GB to a normal VHS-tape. Quick search around the net didn't find much other than LGRs video and random snippets, but apparently that was slow, roughly 4MB/minute. But at the time when a lot of people didn't even have storage on their computers up to gigabytes, so it could've been a viable option, but I haven't heard about anyone who'd actually used a thing like that.

C-cassettes on Commodre 64 were a common thing and in here even the national broadcasting company sent some programs over the FM radio during nights.