qBittorrent - Lightweight and open source torrent client that runs on all major platforms.
FrostWire - Easy to use BitTorrent Client and YouTube Downloader in one, with built-in search and music library.
Deluge - Deluge is a full-featured BitTorrent client for Linux, Unix and Windows.
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)
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
aria2 - aria2 is a lightweight multi-protocol & multi-source command-line download utility. It supports HTTP/HTTPS, FTP, SFTP, BitTorrent and Metalink.