my top answer to this is always toramaru from ina11—he does have /some/ content, but it's not enough for someone as cute as he is.

another one is sian from tales of innocence—i love feral boys. the game itself is def one of the lesser known tales games since its mobile and never got an official eng release, and he's also a side chara, so i get why he's lesser known.

third would be younger apollo from aa6. i love apollo in general (he's the main reason i even picked up the aa games) but when i played SoJ, i got thirsty for shotapollo content and have never been quenched lol.

and last would be younger ryu from bof3. this is maybe not so much about ryu himself, but about wishing for more content with rei, ryu, and teepo with specifically brocon flavoring lmao.