Some of My Sons German Stamps

My 10-year-old son has many stamps that were donated to him and also given to him as gifts. This is just a very few of the selection. I know that they are German stamps but I really know nothing about them and he doesn't know much about them either except that he likes them very much. He has been collecting stamps of all kinds from all different dates and from all different countries all across the world , including coins, plates , rocks ect.... Even though he really knows nothing about these particular stamps; there are many stamps that he has collected that he knows very much about and has studied about them but these are just a few that he knows only that they are from Germany .