As far as usable access (from a genetic genealogy point of view) and consistent analysis method, FTDNA's database is going to be hard to beat. You can find their samples under "Ancient Connections" per haplogroup you are interested in on their Discover tool.
https://discover.familytreedna.com/
They wouldn't be the place to access raw data from but they cite the studies they take each sample from.
Their last blog update says they have almost 4200 ancient samples analyzed. These are all ancient men, I believe.