aria2 is a lightweight multi-protocol & multi-source command-line download utility. It supports HTTP/HTTPS, FTP, SFTP, BitTorrent and Metalink, etc.
License: Open Source
Aria2 is an open-source, command-line based downloader that supports multiple protocols and is lightweight, making it ideal for advanced users. In contrast, µTorrent is a popular torrent client known for its user-friendly interface and advanced features, but it includes ads in its free version and has a more complex setup for some functionalities.