No one can really guarantee any given model drive will work with these devices apart from whatever Buffalo certified back in the day.....however they seem to work with most sata drives, even those much newer than the devices themselves.
These devices can boot from GPT partitioned drives, so they shouldn't have the 2TB drive limit that some older devices had (even those could sometimes be worked around).
These devices are running 32-bit ARM which limits them to 16TB per volume. So theoretically you could have 4 16TB drives configured individually but only 4x4TB drives in a 16TB RAID0 etc.
I have briefly tested some WD blue/red/etc drives in these devices up to 8tb and they seemed to work.
