A really cool branch of comic-collecting is the group that collects artist and creator signatures. This can be a lot of fun and adds to the uniqueness of a comic book. For example, if you can get a Captain America book signed by Joe Simon, Jack Kirby, Stan Lee, and John Romita Sr., that would be amazing. Simon and Kriby created Cap and Stan Lee and Romita Sr. did a lot of work on the title as well.
Kriby died before certifications by CGC were available, however a number of collectors took their Kirby-signed Caps and had them signed by the other living creators, certified by CGC. The window for that has closed as Joe Simon passed in 2011, a dark moment in the history of comics. So you can just imagine how rare these combinations of signatures really are. It's a just awesome to see them.
I don't have one to show, but I will show a certified Joe Simon in the article picture.