I've found that a lot of devices anymore just pack in those no-name power supplies. Many things don't even ship with branded PSUs now. It makes sorting my box-o-wallwarts a giant pain in the ass.
This is the opposite of my strategy: each wall wart in my box gets a legible label with voltage and ampacity. Eg 9V 200mA, 12V 500mA, etc. Each device gets a corresponding legible label with its required voltage and maximum current.
Then it's just a matter of picking out one that's adequate for the selected device, it's a many-to-many mapping with lots of valid solutions, not one-to-one.
Edit: don't repeat myself