- The Mime was well-liked in the preview. Even more in the episode proper thanks to his entertaining animations and resourceful moveset. He is also Thomas Astruc's favorite villain.
- Of the five main characters (Marinette, Adrien, Alya, Nino, and Chloe), Nino Lahiffe is the one who appears the least in official merchandise and gets the least focus in the show. He's also arguably the only one who hasn't fallen into Base-Breaking Character territory yet, thanks to his positive attitude, his overall healthy and supportive friendship with Adrien (heck, his first akumatization came about because he wanted to throw Adrien a birthday party), and his getting the Turtle Miraculous, all of which make him a fan favorite.
- Marinette and Adrien's classmates tend not to get much focus outside of episodes where they either get akumatized or get a Miraculous, but several of them have gained a large number of fans:
- Nathaniel was already quite popular despite being a background character with barely a couple minutes of screentime. Then "Evillustrator" revealed that he had a one-sided crush on Marinette, and his turn as the Villain of the Week saw him get an ingenious skillset. His popularity has increased dramatically since then.
- Juleka and Rose have a lot of fans, thanks to the heavy implications that they're a couple.
- Alix Kubdel is well-loved by fans for her snarky demeanor, her occasionally being the Only Sane Man to the class, and (as of "Reverser") her close friendship with fellow dark horse Nathaniel. "Timetagger" only saw her popularity increase, thanks to the reveal that she'd get the Rabbit Miraculous in the future.
- Rogercop, for his Pay Evil unto Evil crusade against the Screw the Rules, I Have Connections! Mayor and his Alpha Bitch daughter Chloé.
- Prince Ali also gets a lot of fan attention for a character who only appears in one episode. Then again, it does help that the writers clearly never forget about him, since he was mentioned from time to time after his debut, and finally made other reappearances in "Heart Hunter" and "Lies".
- Both Markov and his akumatized counterpart, Robostus, the first one for being absolutely adorable and having a sympathetic plight, and the second one for his absolutely brutal but efficient conquest of Paris, near-victory over Ladybug and Cat Noir, and actually turning on Hawk Moth and coming close to murdering him.
- Marc became popular as soon as his debut episode aired, thanks to his adorkableness, his shyness, and the paper-thin subtext in his relationship with Nathaniel.
- Mireille Caquet and especially Aurore Beauréal have many fans, likely due to being central characters in the very first episode. Some are even hoping that the latter will get a Miraculous one day.
- Jagged Stone, his pet crocodile Fang and his agent Penny Rolling are also quite popular.
- For characters that ultimately never made it into the final show, Félix (the original Cat Noir) and the Quantic Kids (Melodie, Mercury, Sparrow, and Kid Mime) have their own surprisingly strong fanbase. Ultimately, Félix ended up appearing in the show in season 3 (with an episode named after him, to boot), while Sparrow ended up debuting in the Miraculous New York special (alongside Mercury as a background character).
- The Gorilla is well-loved by fans for being just about the only positive adult influence in Adrien's life (with Gabriel and Nathalie being supervillains and the former being emotionally abusive).
- Sentibug (the Fan Nickname for the sentimonster Ladybug created in "Ladybug") is beloved by fans and the subject of many an AU where she manages to live past her debut episode.
- "Miraculous New York" gave us Majestia, Knightowl, Sparrow, and Uncanny Valley, all of whom gained a number of fans pretty much the moment they debuted — the former two for essentially being Superman and Batman as a lesbian couple, the latter two for being adorkable young heroes (Sparrow especially for being a rare example of a major Native American character in animation and eventually wielding a Miraculous of her own).
Ensemble Dark Horse / Miraculous Ladybug