Character Recommendations Based on Sheldon J. Plankton
Sirius Black Harry Potter Series

An escaped convict on a mission, Sirius is brooding, brave, and reckless
E.T. E.T. the Extra-Terrestrial

This cheerful alien just wants to phone home
Augustus Waters The Fault in Our Stars

Charming and confident, Gus lives in fear of never leaving a lasting mark on the world
Kat Stratford 10 Things I Hate About You

Part of the "out" crowd and proud of it
Ron Swanson Parks and Recreation

The man's man's man's man
Sandy Olsen Grease

Wholesome and pure but also scared and unsure
Penny The Big Bang Theory

The girl next door, literally
Sharpay Evans High School Musical

She's queen of the stage, and not aiming to be replaced
Tobias "Four" Eaton Divergent

He's only afraid of four things, but you should probably be afraid of him
Sherlock Holmes Sherlock

This wildly brilliant detective can figure out everything except how to interact with other human beings