Here’s a list from the creator. I’m not sure if they’re all always there:
"Here is the semi-official list of symbols, more or less in order of frequency of use: eyeball, piece of pie, alien, dynamite, K2, upside-down bird, bunny head, crown, single shoe, arrow in the back.
They began in 1996 when I decided out of boredom to draw a little bird sitting on a shelf where it didn’t really belong"
Did you know that every Bizarro comic has a hidden eyeball (bottom right), alien (top right) and piece of pie (can’t find it in this one)?
please tell me this is true, I’ve been looking for the pie for 5 minutes now
Here’s a list from the creator. I’m not sure if they’re all always there:
"Here is the semi-official list of symbols, more or less in order of frequency of use: eyeball, piece of pie, alien, dynamite, K2, upside-down bird, bunny head, crown, single shoe, arrow in the back.
They began in 1996 when I decided out of boredom to draw a little bird sitting on a shelf where it didn’t really belong"
These are examples of the secret symbols you can find in the comics a full list with explanation is on the official bizarro website
They are not all always there, just sometimes. There is a number on the signature which tells how many are hidden for each comic.