This is an odd question, really.
ATX/ATX12V/EPS12V all would apply here. All newer PSU's that you would use in a normal, full size system are ATX, but they will also be either ATX12V or EPS12V (or both at the same time). I don't even know of any newer ATX PSU's that aren't at least ATX12V.
Strange question with no real answer, other than to just get an ATX PSU if you're building a system for a normal sized case.
I think you're letting PC Part Picker confuse you. Don't.
All you need to know is that you want an ATX PSU.