Rats on The Boat
Rats on The Boat – free and open source BitTorrent P2P multi-platform search engine for Desktop with integrated torrent client
Tribler
Tribler is an free and open source software project facilitating searching, streaming and sharing content using P2P technology
WebTorrent Desktop
WebTorrent Desktop is a free and open source streaming torrent client for the desktop
KTorrent
KTorrent – free and open source BitTorrent client by KDE. It allows you to run multiple torrents at the same time and its features can be extended by plugins
qBittorrent
qBittorrent – cross-platform free and open source software alternative to µTorrent. BitTorrent file sharing network client. Torrent client with a built-in search engine