We got a question about setting a unique Sort Order when viewing a list. (We were looking at Item List at the time.)
The answer is “mostly-no”. You CAN choose the field that the list uses to sort and then you can set ASCending or DESCending. (See: https://docs.erpnext.com/docs/user/manual/en/customize-erpnext/articles/customizing-sorting-order-in-the-list-view.)
But they were after a “Custom Sort Order” that could take something like 1, 10, 100, 2, 20, 3 and sort it as 1, 2, 3, 10, 20, 100.
Custom Sort Order is not available “out of the box” as they say. We could code it up but it didn’t sound critical to you so I will wait for you to ask for it.