One example is 'Watchmen' by Alan Moore. It has complex characters with morally grey areas. Rorschach, for instance, has his own extreme sense of justice that many might not consider 'redeemable' in the traditional sense.
One aspect that can make an irredeemable graphic novel stand out is its unique and often dark or complex themes. It might explore moral ambiguity in a way that other graphic novels don't. For example, it could have characters with no clear path to redemption, which is quite different from the typical hero - villain dynamic in many mainstream graphic novels.
You might try looking in specialized libraries or archives dedicated to cartoons and animation. Some universities or cultural institutions might have such collections.
A retrato caricatura is more exaggerated and focuses on highlighting certain features for humor or emphasis. A traditional portrait aims for a realistic representation.