I see several people have already mentioned Soulseek, the one other place I’d recommend is rutracker. You have to sign up, and it’s in Russian, but it’s probably the easiest place to grab entire discographies, and you can occasionally find things there that aren’t on Soulseek.

Of course if you’re really serious about music piracy, getting into the private tracker scene is the only way to go. redacted.ch specifically, is probably the most comprehensive music archive on the Internet right now.

Edit: I just realized no one has mentioned stream rippers yet. If what you want is on a steaming service like Deezer or Qobuz, and hasn’t been shared elsewhere, there are tools to download it directly from the streaming service in full quality. Getting these set up can get a bit technical, and they often require a premium account, but there are Discord and Telegram bots that act as a fronted for these tools running on a server somewhere, which is the easiest way to use them.