Assume an unlimited budget for now, I just want to know what's out there.
I mean, if you're willing to pay the price of a car per SSD they go up to at least 122TB density per drive... (e.g. Solidigm SBFPF2BV0P12001 D5-P5336 -- $16K~$20K depending on supplier from a quick search)
I don't actually recommend that for personal use, but since you were curious about what's out there, there's some absolutely crazy shit in enterprise server gear if you have deep enough pockets.