I bought some over the years on eBay that came out before my time. Some I bought from collectors downsizing. I was lucky enough to have a mentor who retired and gave me some of Mosaic sets. The more recent titles I bought as they came out over the last 10-15 years which have been mostly CDs, but there were some vinyl sets like Coltrane's Sun Ship, which I'm lucky enough to have a test pressing of.
I had a Flickr gallery where I used to post my Mosaic sets, but that was over a decade ago when things were still manageable.
The Flickr gallery is still up ---> Mosaic Records Boxsets