I picked up some of the last of the T.H. X-18 from Breeders Retail. As I recall there were no more to be had, from a retail perspective, that I am aware of.
I also picked up the PTK reproductions by Verdant Green from the same source.
Unfortunately BR closed shop last December and I am not aware of another source for VGSeeds. You might shoot him a PM and ask.
Another possible source for PTK repro beans is from CSI Humboldt, aka Inspecta. I know he documented a big PTK project on insta but not sure what he did with the seed. I think it was kept in house but again, asking him would be the most reliable route to the correct info.