Only superfans know every single thing Jim Henson created during his storied career, but in this case ignorance is a good thing- because it gives the rest of us an excuse to look into his lesser known creations.
You may remember the Swedish Chef endorsed Cröonchy Stars cereal released in the late 80s, but I had no idea the cereal was actually created by Henson and art director Michael Frith.
Jim wasn't averse to working in advertising, and early in his career he was asked to create a series of ads for Wilkins Coffee starring Wilkins and Wontkins, two of Henson's earliest puppet creations.
Although he's best known for his puppets Jim started out as a cartoonist, and some of Henson's earliest illustrative work can be seen in his comic strip Pierre the French Rat, which was printed in his high school yearbook. (See full sized image here)
Henson was a huge fan of comic strips, so he helped create a pilot for a TV adaptation of the popular Parker and Hart strip The Wizard of Id, but networks took so long to pick up the series Jim had already moved on to making Sesame Street.