Many webcomics that use CGI models, such as in Poser or DAZ Studio, are subject to this. Poser simply has big problems with the Valley, since depending on the skill of the artist using it, the quality of the figure textures and morphs he/she is using (there are literally thousands of morphs and textures available for the popular base figure such as Daz 3 D's Victoria and Michael series and the quality is just as widely varying), and the amount of time and money he or she is willing to invest in creating panels, it can range from passable to downright horrifying.
Lil' Cal is described as being in "the Uncanny Laurentian Abyss". Really, though, if Mr. Hussie wishes to use this, you will know: for instance, a Diagram; a self-portrait intended to disturb; the Duttle... the list could go on and on.
While she's an alien species probably best described as "a green skull monster," Calliope tends to stay away from the Valley due to her sweet mannerisms. Caliborn, on the other hand...
No Face from YU+ME: dream is an easily accomplished attempt at making something human, but disgustingly monstrous. He also eats hearts, just to add to the (puneriffic) images of terror.
Part the appeal of The Order of the Stick is that it inverts uncanny valley by having cartoon stick figures who are clearly unrealistic looking while showing human qualities, which endears readers to them.
Arguably, the characters fall to the left of the valley, as they are cartoony enough to avoid being uncanny.
Gunnerkrigg Court: When Jones reveals to Annie that she's not human and can't feel emotions, we (or at least Annie) also find out why she never seems to smile (or rather why she doesn't bother trying to mimic emotions). This bonus strip is fittingly named "Uncanny Jonsey".
Kiwi Blitz: used to describe android girl 42 on the cast page.