This website from two professor at the University of Kentucky collects references of elements in graphic novels. Some, like Metal Men, are chemistry specific comics but there are also appearances in mainstream comics from Batman and Scrooge McDuck. The nefarious elemental plots seem to outnumber those where chemistry saves the day. Most of the comics date from 1940 to 1970, with a few of more recent vintage. They don't seem to be updating anymore, but this is a fun collection to browse through.
