It's worth noting that the Internet Archive are always on the lookout for more records to digitize, so if you (or someone you know) has a collection and wants to see them go to a good home where they'll be preserved, you can donate them [1] to the Internet Archive (they also take 33/45rpm records, books, CDs, etc...). (I'm not affiliated with the Internet Archive) [1] https://help.archive.org/hc/en-us/articles/360017…
* https://www.abc.net.au/news/2018-06-18/australias-largest-re...
Though this article from 2016 indicates one Zero Freitas has six million "in a 25,000-square-foot former candle factory in São Paulo":
* https://www.reedyoung.com/vinyl/
* https://en.wikipedia.org/wiki/Zero_Freitas
A 2013 article about John Tefteller, "who has stockpiled over 75,000 blues and rock & roll 78s":
* https://www.factmag.com/2013/10/01/tommy-johnson-blues-becom...
See also this 2009 documentary about Paul Mawhinney, who had three million items, and which was sold to Freitas: