FrostWire - Easy to use BitTorrent Client and YouTube Downloader in one, with built-in search and music library.
rTorrent - rtorrent is a BitTorrent client for ncurses, using the libtorrent library.
µTorrent - Looking for a torrent site to download movies, music and more? Choose from top torrent sites like The Pirate Bay, RARBG, 1337X, and dozens more. (October 2019)
BiglyBT - BiglyBT is a feature filled, open source, bittorrent client. Auto migrate from Vuze and Azureus. I2P integration, Swarm Merging, Advanced Tag System, WebTorrent support, built-in VPN kill switch, Meta-search, UPnP/DLNA access, and much more.
Deluge - Deluge is a full-featured BitTorrent client for Linux, Unix and Windows.
qBittorrent - Lightweight and open source torrent client that runs on all major platforms.