Paper Mario - They Don't Think It Be Like This, But It Do

Thousand-Year Door has the most variety while colour splash looks like they just traces Toad and added bits and bobbles with a few colour changes, just look at the outlines of them and you can see it how they just go "meh"

you can see it in the concept art, they tried but someone has a leash on them all the time

Notice how, other than the sentai Toads and the ones in overalls, they all share the same basic Toad design, except recolored/with a funny hat. And it doesn't account for the fact that 70% of the Toads in the game are the same generic red cap, blue vest design.