SALI (Sara Automatic Linux Installer) is a tool that allows you to install Linux on multiple machines at once. It support several protocols for downloading by way of aria2 to install a machine. For example, BitTorrent and rsync are supported. SALI originates from SystemImager and still uses the same philosophy. It is a scalable method for performing unattended installation. SALI is mostly used in cluster setups.
PeerProject is a versatile peer-to-peer filesharing client and file manager. It's intuitive and aesthetic while supporting many networks and features, including BitTorrent, G2, Gnutella, eDonkey, DC++, IRC, HTTP/FTP, and more. It's a mainstream fork of Shareaza p2p, for Windows and WINE.
Btpd is a utility for sharing files over the BitTorrent network protocol. It runs in daemon mode, thus needing no controlling terminal or GUI. Instead, the daemon is controlled by the btcli command line utility or other programs capable of sending commands and queries on the btpd control socket.
PyroScope is a collection of tools for the BitTorrent protocol and especially the rTorrent client. "pyrocore" is the component providing command line tools for automation of common tasks, like metafile creation, and controlling rTorrent via its XML-RPC interface. It also offers a documented API, with which these tools are implemented.
pytvshows downloads torrents for TV shows from RSS feeds provided by ezrss.it (previously tvRSS.net). It is designed to be run from cron or a shell and interfaces with BitTorrent clients like Transmission (via the Transmission RPC API) or any other BitTorrent client that supports folder monitoring (most). This is a resurrection of the venerable pytvshows script by Ben Firshman.