Some people like to collect stamps of maybe any one country or lots of countries, but which are all of the same subject, or topic. These can be a lot of fun, and also an inexpensive way of getting to know about the stamps of many countries. Take birds , for example. There are thousands of different stamps showing birds. Space craft are not so common, but there are still many stamps showing those.
Sports is another topic shown on the stamps of all countries.
When you want to get fancy, maybe you would like to collect stamps of just one sport, like soccer. Or, maybe just stamps of the Olympic Games. A long time ago, the mark might have been made by running a pen over the stamp. Well, some people collect stamps that have interesting cancellations on them. Your goal might be to find a stamp cancelled from Dandelion for every year you can, or every month if you want.