Cartoonish Companions

Alice and Bob are your ordinary action cartoon protagonists, drawn perhaps between five and seven heads high: not quite a Heroic Build, but roughly approximating real life proportions. The audience is meant to empathize with them, so their appearance is pretty typical as humans go, and so is that of most of their friends.

But here comes their good pal Charlie, and something's off about him. He's not quite a Gonk, but his looks are totally at odds with the style in which Alice and Bob are drawn- he's anywhere from just a single head shorter than the "normal" characters, to a mere one head tall. His face is drawn in a more comical style, with some features exaggerated beyond the norm, with a Gag Nose or beady eyes where other characters have petite noses and wide eyes. Although he stands out at first, there are other characters here and there who match his design standards, so he's not an example of Non-Standard Character Design, especially since Alice and Bob don't seem to see anything unusual about his appearance. In short, Charlie is a Cartoonish Companion.

Cartoonish Companions are distinct from Super-Deformed types and other Fun Size characters in that they are rarely deliberately cute, and although some gags may play on their diminutive stature, their looks are rarely noted as anything unusual within their world.

They are often Sidekicks or Plucky Comic Relief. Miniature Senior Citizens is a subtrope.

This Needs More Examples

Examples of Cartoonish Companions include:

Anime and Manga

Musashi, the first Getter 3 pilot was gonkier and shorter than the other pilots, looking pretty out-of-place, although later adaptations tend to draw him less cartoony and more stout. Benkei's just a little less shorter and stouter than Ryoma and Hayato, and Gai towers over all the others.
Chitan of Katteni Kaizo is a perfect/totally straight example of this.
Leiji Matsumoto: Tetsuro from Galaxy Express 999 and Toshiro from Space Pirate Captain Harlock are broad-mouthed, beady-eyed, plump, and half the height of their otherwise tall, slender, and fine-featured comrades.
Oh! Edo Rocket: Roughly half the main cast stands less than half the height of the remaining cast.
Osamu Tezuka: Leaving aside how he drew himself, Tezuka's star system is littered with characters of this sort, especially Professor Ochanomizu and Shunsaku Ban.
In Even a Monkey Can Draw Manga, it is "recommended" (all of the "rules" in the work are actually cliches that the authors think shouldn't be done) that the shonen hero's comic sidekick be one of these.

Comic Books

Bone. The three Bone cousins are blobby cartoon characters who obey cartoon logic (like Fone Bone's head assuming the shape of a pie when Phoney shoves it into his mouth). Everybody else is drawn in a more realistic, though stylized, fashion. This is due to the influence of classic comic strips like Pogo and Li'l Abner on Jeff Smith.
DC Comics writers and artists like to play with this in the appearance of Fifth Dimension imps like Comic Books/Batman's Bat-Mite and Mister Mxyzptlk of Comic Books/Superman. How strange they appear to ordinary humans varies from writer to writer.
Green Lantern: Golden Age Green Lantern Alan Scott's frequent companion Doiby Dickles was so much shorter than the ordinarily proportioned villains that he had to jump up to properly place his fists when getting into a brawl.
Of the Metal Men, Gold and Platnium are the closest to humans in terms of design. Justified Trope in that they are all robots.
Plastic Man: Woozy Winks lived up to his role as the Plucky Comic Relief to a Plucky Comic Relief superhero by having an even more absurdly cartoonish appearance than a man made of living rubber.
In the old The Spirit comics, The Spirit's sidekick was a very cartoonish, minstrel-looking black kid named Ebony White.

Film

Beauty and the Beast: Belle and Gaston are realistically designed, while the other villagers are slightly more cartoony, emphatizing the former two characters' atractiveness. However, Gaston's lackey Lefou takes the cake; he can only reach to Gaston's waist, has huge googley eyes, a pink bulbous nose, and buck teeth that would look more reasonable on Goofy.
Eight Crazy Nights: Whitey is about half the size of any other adult.
In Max Fleischer's Gulliver's Travels, Gulliver is drawn hyperrealistically through rotoscoping, the Prince & Princess are drawn fairly realistically from models, and the rest are drawn in cartoony styles.
In Snow White and The Seven Dwarfs, Snow White, the Prince, the Queen, and the Huntsman are drawn in a serious, "realistic" style, and have five fingers. The dwarfs—well, they are dwarfs, but they hardly come up past Snow White's knees, and are drawn in a more comical, cartoony style with Four-Fingered Hands.
In The Prince of Egypt, most of the cast are fairly realistically proportioned, with the exception of the Fat and Skinny Egyptian priests Hotep and Huy.

Video Games

Professor Layton: the recurring cast and major characters for the game are normal enough, but the random NPCs (The ones with the primary purpose of giving puzzles) tend to be much more strangely shaped for the benefit of Cast of Snowflakes. Justifed in Curious Village by being robots, with the few that aren't odd shaped being based on existing humans, it doesn't explain the kid sized "explorer" you encounter a few times as he explicitly is human

Webcomics

Sinfest: Many of the characters, including Slick, Semyor, Lil' E, Squig, and Criminy are if somewhat... diminutative stature, but most of the other characters have normal porportions, porportions which even these characters gain when they enter the Reality Zone (Excpet Squig, of course)

Western Animation

Teen Titans: Larry takes the mischievous Great Gazoo relationship between Bat-Mite and Batman and brings it to the world of animation as Robin's cartoonish imp- taking this trope Up to Eleven, since it isn't in a realistic style to start with, and Larry still manages to look more cartoony than anyone else. Even Beast Boy.
Batman the Brave And The Bold has the Plas/Woozy thing but then there's also Bat-Mite.