Before I ask you to rush out, buy up all the surplus stock, and then stash them away in some cool, dark place, well away from anti-aircraft missile battery radars and stuff like that, we would need to establish exactly what they are.
So called Double Density, so called High Density ... and all the other possibilities. Such details matter to 25 year old disk drives that aspire to work with 8-bit microcomputers of similar vintage.
Maybe you should restrict your purchase to just one box in the first instance and then check them out. OK, don't tell me ... no 5.25" disk drive!
I must admit that I've never really gotten to the bottom of all this stuff, but know a few ... er, wizards who (apparently) have. It's interesting (what isn't), but it's "yesterday's technology", unfortunately.
But wait, better make that "fortunately" ... how many disks (and disk drives) have I tried in recent times, only to be ... um, disappointed
with the results (as in, loss of irrevocable data)!
Also ... see here
! Elephants' graveyard? Sorry Neil, but I can't ship to Jeddah.