If you are looking to test your new FLAC setup, start with the "Big Four":
Buy lossless from official stores
While we don't host files here, the usual archival haunts are buzzing. Sites dedicated to high-fidelity sharing and private torrent trackers are currently seeding comprehensive discography packs. Look for folders labeled or "24bit/96kHz" to ensure you are getting the highest quality currently available. the rolling stones studio discography flac new