Other than double taxation on dividends, what other example of double taxation are there?

The standard usage of the term is the dividend issue. From that point of view, the only other example I can think of is if you made money in one country but reside in another - you might have to pay in both places.

But in practice, things are taxed about a billion times over if you take a serious look at it.

Lots of things have triple, quandruple, etc. taxation. I doubt most people are even aware of how many billions of times over things are taxed. Like being charged property tax on inventory that you have for sale, and then the purchaser has to pay sales tax on it when they buy it. And the company has to pay income tax on the net profits from selling it... I could go on and on.