AllMusic - AllMusic.
Lidarr - Lidarr is a music collection manager for downloading and organizing music libraries.
MP3Juices - MP3Juices is a free mp3 search engine and tool that allows you to download unlimited mp3 files anywhere around the world.
Headphones - Automatic music downloader for SABnzbd. Headphones is an automated music downloader for NZB and Torrent, written in Python. It supports SABnzbd, NZBget, Transmission, µTorrent, Deluge and Blackhole.
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
Lacey - Free Music & Video Downloader