Some of the most popular Xbox 360 DLC packs include:
The original domain is gone, but archived threads via Wayback Machine contain magnet links for full DLC scene releases from 2008–2016. Xbox 360 Dlc Archive
Some notable examples of DLC from the Xbox 360 era include: Xbox 360 DLC Archive — A Short Story
Most community archives store DLC in containing: Read-only REST API for metadata and availability queries,