I don't think this is the kind of question anyone can answer for me, so I guess I'm just looking for some kind of guidance...

I'm trying to create the playable characters in my game (which is a 2D platformer.)

I need this to be a somewhat cartoony and silly aesthetic, so I don't want the characters to have normal human proportions. I need the heads to be bigger to show more detail in the face. The problem is that this isn't what I normally draw, and so now I'm trying to work out of my comfort zone, and I'm struggling to get this right. Especially since I need to be able to animate these characters.

I'm trying to find some good references, but when I try looking for "chibi" the results I get are the ugly-as-hell Super-Deformed characters that look like babies with hookworms. Occasionally I come across some that look like babies, but that still isn't going to work for my game. I can't find any good references that show a range of chibi-deformation, much less one that shows how to properly tweak and deform the body to look right with that proportion.

I've tried drawing some forms, but I'm not getting it right. I wind up with characters that look like children; not child-like in appeal but like actual children. And I experiment a little bit but... nothing looks quite right.

I want something that looks natural. I don't want players to see the game and think that I'm trying to look childish or deformed, but something that just feels... drawn, I suppose. Something that feels natural.

This isn't a matter of simply scaling the body down. I can see that much. I have to tweak things, I suppose girth and length, and not just for the body but for various parts. And since I don't quite know what I need this to look like, I'm really stuck.

I'm working outside of my comfort zone, and I could really use some kind of guidance toward how to find, draw, and model a proper proportion.

(My intent is to look like a drawn image with lines and solid colors; my plan is to make 3D models and animate them, and use special rendering tricks and rotoscoping to produce the game's sprites. So I need this primarily to look right as a drawn character, but also properly exist as a 3D model.)

There are a limited number of possible choices for humanoid bodies, and at this point some game or anime has done all of them. (And I agree that many of them are ugly, though who knows if we'd dislike the same ones. Like, I personally hate maplestory and puzzle pirates avatar styles but like gaia online's avatar style. GO's avatar style is far from universally liked though, and the other two aren't universally disliked either. And I don't like the powerfuff girls style, but many people do. I do like Invader zim's style but many people don't. And so on.) But basically I recommend finding an existing example you like and abstracting the proportions from it. If you want an array of option though, try putting megaman into google image search, he's a very basic-shaped human character who has been illustrated in many proportion styles.