The Adventures of Jimmy Neutron: Libby Folfax

 Liberty Danielle "Libby" Folfax is one of the main characters in The Adventures of Jimmy Neutron: Boy Genius. She is a sassy African American girl first appearing in the Jimmy Neutron: Boy Genius film. She is Cindy's best friend and Sheen's love interest.

Libby's main interest is music with the funky rhythm. When she experiences music withdrawal, she faints (as revealed in "Hall Monster"). She also loves electronic gadgets and being stylish. In the first season, she doesn't appear in the title logo. When she becomes more involved in the show, however, she is added to the logo in the second season and is still on it in the third season. Unlike Jimmy's best friends, Libby is shown to do well in school, but isn't at the level of Jimmy or Cindy in terms of intellect.

Jimmy Neutron: Cindy Vortex

Cindy is Jimmy's simultaneous rival and romantic interest. She is a mixture of a semi-protagonist and antagonist.

Cindy, as said, is a bit of an antagonist in a way, even though she's very smart and competes with Jimmy and she gets jealous of his superior intellect sometimes. She is very prideful, tomboyishly beautiful, stubborn, kind, and persistent, and she was shown with these personality traits throughout the series.