aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent, and Metalink. It has a powerful segmented downloading ability, downloading a file from multiple sources and multiple protocols and utilizing your download bandwidth to the maximum. It supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data while downloading a file like BitTorrent.
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.
KTorrent is a BitTorrent application that allows you to download and share files using the BitTorrent protocol. Key features include queuing of torrents, global and per-torrent speed limits, previewing of certain file types, importing of partially or fully downloaded files, file prioritization for multi-file torrents, selective downloading for multi-file torrents, kick/ban peers with an additional IP Filter dialog for list/edit purposes, UDP tracker support, support for private trackers and torrents, support for µTorrent's peer exchange, support for protocol encryption (compatible with Azureus), support for creating tracker-less torrents, support for distributed hash tables (DHT), support for UPnP to automatically forward ports on a LAN with dynamic assigned hosts, support for webseeds, scripting support via Kross, and interprocess control via DBus interface.
Lince is a light and full featured BitTorrent client. The graphic interface has been designed to resemble the old Azureus, and is simple but powerful and gives the user all of the information in an easy and intuitive way. It is configurable and efficient, using as few resources as necessary.
DragonDisk is a powerful file manager for S3 compatible cloud storage services, such as Amazon S3 and Google Cloud Storage. It allows you to back up, share, and organize your data thanks to an intuitive interface. Features include multiple windows; copy / move between Amazon S3 accounts; a multi-threaded HTTP/HTTPS engine; drag and drop; rename files and folders; filename filters; BiTorrent, time limited, and signed URLs; client side encryption; a metadata editor; ACL inheritance; detailed operations logs; and support for versioning.
Tahoe-LAFS (Least Authority File System) is a decentralized data store. It distributes your filesystem across multiple servers, and even if some of the servers fail or are taken over by an attacker, the entire filesystem continues to work correctly and to preserve your privacy and security.