These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Fillmore!
Anvilicious: The bullying episode "A Dark Score Evened" lacks the more casual writing of the show.
"Test of the Tested" can be seen similarly, especially as standardized tests come under more fire in Real Life. Having tons of the school's kids in total panic mode at the mere thought of a retake didn't quite help.
Wayne, Fillmore's former partner, has a sizable following in fanfic, and Emily, Wayne's partner who was bullied off the force and only had one scene on-screen, has a similar following due to the show leaving how she was bullied and why it was so bad she transferred schools largely unexplained.
Fillmore's catchphrase of "Disco." makes a lot more sense when you realize "disco" is Latin for "I learn."
In "Field Trip of the Just", the suspect is disguised in a South Carolina costume during the final chase, and at one point bumps into someone who asks "Yo, South Carolina, what's the rush? You seceding from the Union or something?" South Carolina was the first state to secede during The American Civil War.
Harsher in Hindsight: "Test of the Tested" once you realize how Real Life standardized tests can affect kids quite similarly, and have lately come under the same kind of fire the S.A.T.T.Y.9 did in the episode for their pressure on kids for a single test.
Leo/Gustav Amaddeus Douglas in "Masterstroke of Malevolance"
Francine Bishop in "The Shreds Fell Like Snowflakes
Kipp in "Foes Don't Forgive"
Penny in "Immune To All But Justice"
Oskar Mabini and Robert Chestnut in "Links in a Chain of Honor"
Terri in "The Unseen Reflection"
Yumi and Gladys/Alexis in "Codename: Electric Haricut"
The vigilante perpetrators in "A Dark Score Evened" - all of them have genuinely been shafted by the system, they have a Token Good Teammate and the only one who truly qualifies as a Jerk Ass is their leader.
Alexandria in "Field Trip of the Just"
Not So Harmless: While most of the culprits are completely harmless, Francine Bishop nearly killed Fillmore. Twice. Though the first time she probably didn't plan it.
Shipper on Deck: Wayne Ligget ships Fillmore/Ingrid. Without knowing Ingrid, only having read about her in Fillmore's letter.