General Inventory ITS:
https://www.its-arolsen.org/en/archives/overview-of-the-archival-holdings/general-inventory/
The International Tracing Service says it has published its Holocaust-era inventory online, offering an overview of holdings that include some 30 million documents on Nazi persecution, forced labor and the fates of survivors.
More:
http://www.timesofisrael.com/german-holocaust-archive-publishes-inventory-online/