There was such a thing round 2007-2010. People on forums were opening free email accounts, then a desktop app was splitting files into chunks of predefined size and uploading them as emails. Individually each chunk was an encrypted chuink of 7z or zip archive, so it made no sense on its own, but the client was building a repository of email account and email IDs. This index was then shared with other people on a forum and you could download Shrek.

https://forums.freebsd.org/threads/peer-2-mail-file-sharing-...

https://www.ygoow.com/index.php?lang=en