Manufacturers create so many different plug designs for devices. I think their purpose is to make it difficult for customers to do anything to make the batteries explode or start fires (which news reports frequently mention about Li-on type).
There are a couple options but they are not easy of success:
a) Cut off plug and wiring to original charger that came with device. Splice it to your own charger. This requires extreme care. Even if you succeed, device can no longer be charged from its designed charger. You must carry your multiple charger along on trips. And you must keep it operating because if a key component breaks then you can no longer charge any of your devices.
b) Shop for duplicate plug. It must have exact same dimensions as original plug which fits device. Expense may be high.
Sources you can try include manufacturer direct mail, manufacturer brand store, Radio Shack, Ebay, Amazon, electronics supply mail order, etc.
Success may be impossible unless it's a widely-used standard type.