I grew up with Peanuts as a child where I had some of the books such as Peanuts encyclopedias (these are lost now) as well as some Peanuts comic books and a shirt. Peanuts is actually a very lucrative comic strip franchise and brand where it has spawned not only several animated adaptations but also lots of merchandise ranging from soft toys to action figures, tie-in comics and more. Peanuts has been the subject of a tie-in comic book series since the 60s or something as published by Dell Comics, which shows you how popular and lucrative Peanuts is as a franchise. That’s been done again by Boom Studios, some of which are adaptations of films that never came to be.
They still make Peanuts merchandise but there are others who’re selling off their old Peanuts collection, whether if I wanted to collect these or not. (That’s probably the same with Garfield collectors and Garfield merchandise, as far as I know about it there are serious Garfield collectors out there in the world.) So far, the Peanuts brand has encompassed not only the comic strip but also associated books (encyclopedias, compilations and original graphic novels) but also toys, clothing (I have one upstairs), drinking ware, food and others. The brand has done well for itself and for the heirs of Charles Schulz, the strip’s creator.
Sometime ago, Sony Japan bought some stake in the Peanuts brand (which was mostly owned by another company) since the brand did so well in Japan. However, Schulz’s heirs own around 20 % of the brand with the rest taken up by other companies. That goes to show you how lucrative and appealing the Peanuts brand is.