The Textbook Collection from @Thoth_metadata@hcommons.social is now indexed into : https://oersi.org/pages/de/blog/2025/09/16/thoth/

The collection currently consists of 93 OER Textbooks and every new open textbook that is added to Thoth will automatically be indexed by OERSI too:
https://oersi.org/resources/?provider=%5B%22Thoth%22%5D