FreeBSD used to release official torrents of ISOs, but the torrent server was taken offline due to a data center migration last year and wasn't ever restored.

I suggested putting magnet links on the download page so they wouldn't need to run a separate server to seed the torrents; as a bonus, they'd be able to use the "web seed" functionality supported by many torrent clients to seed the ISOs from their existing distribution infrastructure.

Discussion on the FreeBSD Forums: http://forums.freebsd.org/viewtopic.php?f=3&t=35711