Lolbit. They're an orange-and-purple Palette Swap of Funtime Foxy with Glowing Eyes of Doom like Marionette and Golden Freddy. Their only role is to sell items to the player, and yet they seem just as popular to draw as the original Foxy! Plus, being a recolor of Mangle and all, they've been drawn as both genders. This may be why they became an Ascended Extra and were included in two of thefollowing games.
Helpy, the adorable little Funtime Freddy-esque animatronic who helps the player while they're managing the pizzeria. Fans find him absolutely adorable, sweet and well helpful; it also helps that he's one of the few animatronics that doesn't hurt or hinder the player in any way (except in Ultimate Custom Night). Fans were quite overjoyed to see the little guy become sort of a mascot for Fazbear Entertainment thanks to his appearances in Help Wanted and Security Breach.
Music Man is among the most popular buyable animatronics for his intensely creepy design, even by this series' standards. He was even ascended to a threat in the form of a counterpart in Security Breach.
Mr. Hippo has certainly spiked in popularity with his kill screens and monologues.
To a lesser extent, all of the Mediocre Melodies have gained newfound popularity for their personalities given via their death quotes. Plenty of fanart with them showed up on the FNaF subreddit in Reddit. The two biggest examples are Orville, due to his appearances in Mr. Hippo's stories, and Pigpatch, due to his banjo solos in his death quotes.
DJ Music Man is arguably only behind the Daycare Attendant in popularity regarding enemies in the game — in spite of only appearing in a single isolated area, his shocking appearance, the highly praised music playing in the background of his boss fight, and terrifying chase sequences made him a memorable foe to many players.
For extra points: players returning to the Arcade note that DJ Music Man no longer chases you around, but instead chills out at his stage playing music. With DJMM being one of the few animatronics that stops being violent after his introduction, players like to assume he really is the decent guy Freddy says he is.
Giga Monty, an extremely aggressive version of Monty who appears via Sequence Breaking and can be cloned into a horde, took on a life of his own thanks to a sizeable number of fans who love the concept of a Super-Persistent Predator animatronic, on top of the absurdity of how he exists in the game in the first place. Many of these fans express that the idea of a horde of animatronics who will chase you down upon being activated, with you being completely helpless to do anything as you hear the stampede get louder, is genuinely one of the most terrifying things in the game.
The Wet Floor sign bots barely even qualify as characters, yet they still get fanart, thanks in no small part to their oddly cute design and Dawko affectionately dubbing them "Pat Pats" in his playthrough. YooTooz even made it a collectible figurine and pin.
Between it being a memorable instance of FNaFplayfully lampooning its own jumpscares and its insistence that Gregory take a map (to the point that it can outright tear him out of Freddy, something no other animatronic except for Moon can do, just for a chance to push its wares), the Map Bot has garnered more than its fair share of fans. Some were even a little disappointed when it was announced that the Map Bot wouldn't be returning in Ruin.
