If you look long enough, maybe you’ll find Stan Lee or Alan Moore
The Hollywood Reporter shares this ginormous poster that Fox released to celebrate the 20th anniversary of the Simpsons, featuring everyone from Radioactive Man to Maggie’s nemesis, the kid with one eyebrow. You can find the full-size version here.
(I should add, I have no idea if Alan Moore, Stan Lee or any of the other comic folks who have appeared on the show are really there or not; I started to get a headache from looking it for so long and had to stop looking. So let me know if you find them!)