How many kinds of travel charger there are in the world?

Based on the appearance, there are thousands of kind of travel charger.

But for socket standard, there are mainly 4 kinds, they are AU, EU, US and UK.

And for output value, there are 7 kinds, 700A, 800A, 1A, 1.2A, 2.1A, 3.1A, 5.1A.