Reddit mentions of Stanley 30309 Heavy Duty Triangle Tap, Grounded 3-Outlet Adapter, Black

Really depends on what your end goal looks like and how much connectivity you need. Personally in an attempt to save as much $ as I can I would probably look for a basic desktop system with at least 6 on board sata ports and lots of usb 3.0 or better connectivity. The ones that have a seperate usb 3.1 controller are great because you get 2 controllers to route traffic through. You can also add more sata or usb connections using the available PCI-E slots.

For drives I'd just buy a boat load of the Seagate 8tb externals. Some can be cracked open and plugged into your sata ports and the rest can be plugged into whatever USB ports you have. If you buy some of the ones that have the built in USB hub it's ussualy only a couple of dollars more and makes it easy to daisy chain 2 drives onto each of the hub drives giving you 3 drives per USB port. You could chain more but I find 3 to be a good number per port to avoid too many bottlenecks. For powering all of my adapters I use a 1 to 4 plug splitter like this https://www.amazon.com/gp/product/B01K3ADZ76 with 4 3 way splitters like this https://www.amazon.com/gp/product/B00ALSMFO0 Let's me plug in 12 drives without taking up a bunch of outlets. This worked a lot better for me than trying to run multiple drives from a single larger power brick.

use a cube tap