I’ve uploaded two hour-long audio files to the Internet Archive: York University Libraries Ambiences.
These are recordings of ambient environmental sounds and room tones at York University Libraries in Toronto, Canada.
The first was made in the Steacie Science and Engine ring Library on 28 August 2019. It was closed, but sounds from outside came in through the wall. The second was made in the Clara Thomas Archives and Special Collections vault on 21 October 2019. No people were in the vault, so only the air circulation system can be heard.
Anyone who usually works or studies at York University but is now at home and misses the sounds of the libraries and archives can use these to provide some comforting background sound. Others may enjoy them too.
The files are CC BY. I will check my sound archives and see what else I might be able to add.