One of the biggest, and one of the oldest, taxes in this latter sense is inflation. Governments have stolen their people's resources this way, not just for centuries, but for thousands of years.
Hyperinflation can take virtually your entire life's savings, without the government having to bother raising the official tax rate at all. The Weimar Republic in Germany in the 1920s had thousands of printing presses turning out vast amounts of money, which the government could then spend to pay for whatever it wanted to pay for.
Of course, prices skyrocketed with vastly more money in circulation. Many people's life savings would not buy a loaf of bread. For all practical purposes, they had been robbed, big time.
A rising demagogue coined the phrase "starving billionaires," because even a billion Deutschmarks was not enough to feed your family. That demagogue was Adolf Hitler, and the public's loss of faith in their irresponsible government may well have contributed toward his Nazi movement's growth.
Most inflation does not reach that level, but the government can quietly steal a lot of your wealth with much lower rates of inflation. For example a $100 bill at the end of the 20th century would buy less than a $20 bill would buy in 1960.
If you put $1,000 in your piggy bank in 1960 and took it out to spend in 2000, you would discover that your money had, over time, lost 80 percent of its value.
Despite all the political rhetoric today about how nobody's taxes will be raised, except for "the rich," inflation transfers a percentage of everybody's wealth to a government that expands the money supply. Moreover, inflation takes the same percentage from the poorest person in the country as it does from the richest.
That's not all. Income taxes only transfer money from your current income to the government, but it does not touch whatever money you may have saved over the years. With inflation, the government takes the same cut out of both.