>>85288668that's because the people that frequent loud house threads are cartoon little girl fans, a group well known as one of the most autistic, deviant people in any community, they don't really fap to characters as much as use them as venues for their own pre-built loli fetish that's sometimes even too uncomfortable for standard weeaboo lolifags.
they have no reason to look into Gumball because the more humanoid characters are boys and also animals.
monstergirl people are not interested in what amounts to sentient objects because in reality they're just vainilla waifufags and lite-furfags.
also most of the background characters have limited appeal, Carrie has no body and fanart gets by only by personality, Teri is almost the same only with a gimmick nobody uses after a while, same with Jamie, same with Sarah, Molly literally dissapeared for a couple seasons and fatfags got all they could out of her, and Penny went from a walking nut to a jelly bean and doesn't show up, let alone use her powers enough to remember she exists.
most cartoons that get tons of porn of all cast made have relatively easy designs with crazy personalities, in Gumball, characters have crazy designs with down to earth personalities. People aren't interested, most of that porn is out of novelty/challenge.