Get a NAS, you should be using one any way, It makes switching computers extremely easy, you don't have to bother transferring hundreds of TB just install the apps you use and your good to go.
Got space for a PCIe 8x card? Get a lsi2308 and a set of SAS to SATA cables. 8 drives off that bad boy, and actually reliable unlike every single PCI or PCIe SATA card I've ever tried.
That's how I got a free netbook. It had 32GB and could not be expanded. 27GB on it was wasted on windows and office. And then it needed to download an 8GB update.
Owner had to buy a new one, I got the old one for free. It now has 26GB free, with Linux, libreoffice, and developer tools already installed.
I was once wondering where 80gb of my storage went when I was reinstalling a game, and I eventually found out it was because I forgot to delete the .rar archive after I extracted it.
Small stuff (arguably) like that always fills my disks until it becomes a problem.
slaps desktop PC case
This bad boy can fit so many fuckin drives in it.
slaps shelf
This bad boy can fit so many ... fuck ... crash ... shit