Some individual songs from the LEGO Rock Band setlist have been re-released as "Rock Band Rewind" DLC in the Rock Band Store. How the Export Worked
When active, the process required a unique code found on a flier inside the game case. Lego Rock Band Export
If you purchased the export pack when it was active (roughly between 2009 and 2014), you can still redownload the tracks on the same console family (e.g., from Xbox 360 to Xbox One/Series X). Some individual songs from the LEGO Rock Band