One of the more interesting groups of stamps (historically) that I see here is on the third page of Germany during the hyperinflation period from 1921-1923.
Inflation was rising so fast that the postage rates for the old stamps had to be reset and instead of printing new stamps they overprinted the older stamps with new values. For example I think I see there a red stamp that was originally printed as 500 marks and it has a 250 thousand
mark overprint (revaluation) on the stamp. To the left of it is a green stamp that was originally from when the postage rate was just 1 thousand marks and it is revalued with a 75 thousand mark overprint.
The London Postal Museum briefly describes the stamps from this period of hyperinflation and says, "The cost of a loaf of bread, which had previously cost a mere 250 marks in January 1923; catapulted to 200,000 million (200,000,000,000) marks by November."https://www.postalmuseum.org/blog/s...curiosities/
Inflation kept rising so fast that the stamps became worthless very soon after they were printed, and they still have little value today, but they are a fun relic and souvenir from that little part of history.