Have you tried a comic book store? they're good for browsing, which can be more of a challenge online.

When I was young, I enjoyed classic Disney comics, such as Uncle Scrooge or Donald Duck adventures written by either Carl Barks or Don Rosa. Barks, especially, was something of a genius. My eldest likes these comics, too.

Have you tried Big Nate? My nine-year-old loves Big Nate.