This is the one to look at once you're past eight bays or the array's busy all day, because WD rates it for 550 TB a year and doesn't care how big the box is. Five years of warranty is the other draw, and on a drive you'll leave spinning for most of a decade that's worth having. It's CMR, which is what you want anywhere near a RAID or ZFS rebuild.
!Watch out for
Being 7,200 rpm, it's in the noisier, warmer class of drive, and you'll want it somewhere you don't sit.
Backblaze doesn't run enough of these for a failure rate we'd publish. A 4-bay box full of these gives 24 TB after one drive's worth of parity.
Specifications
Each value links to the Western Digital page or datasheet it came from.