I currently run a Nightmare Before Christmas 1x1 AU RP, with the base plot revolving around Lock. Shock, and Barrel as teenagers and playing off of monster OCs their age. There is literally not a single character in it that I don't like, whether it's the tricksters, the other monster teens, other Halloween Town citizens, and characters we created for later use. That said, I do have my favorites.
Of my partner's characters, that would be Carver.
Carver is a pumpkin-headed creation of Dr. Finklestein's that basically learned how to people from Lock, Shock, and Barrel, and became more or less a fourth member of their group. As her name implies, she's a pumpkin carver who basically started out as a birdcage with a pumpkin head and little arms with Edward Scissorhands-esque hands for her pumpkin carving, with her pumpkin vines serving as makeshift "muscles" to move them. She was meant to stay in one place and carve pumpkins so Finklestein could win the pumpkin carving contest, but she accidentally gained sentience during the activation process. She saw the Corpse family and assumed she was supposed to be a child to Finklestein and his creation, Jewel, but as her creator rejected this role, Carver decided to take her cues from those who were actually her size anyway: Lock, Shock, and Barrel.
She has since gained mobility, and as the trio grew up, she got limb enhancements to "grow" with them (and always makes sure she's a few inches taller than Lock just to piss him off. He's the shortest). Being more or less a genderless robot, Carver is nonbinary, but often uses feminine pronouns for two reasons: it pisses off her creator, who basically intended for her to be a tool and not a sentient being, and to round out the group so Shock isn't the only girl. Ironically, as they grew older and more monsters appeared, most of their social group overall is female. She used to be a sweet, childlike creation, and has since grown into a surly teen who thinks no one understands her but her friends (plot twist: she's not as misunderstood as she thinks. If you've ever seen Meet the Robinsons, Carver is basically Goob. She has that whole, "Hey, Goob! Wanna play?"/"They hated me" mentality. XD).
Carver currently holds the title of Best Character in this game because she's hilarious and a troll. She often keeps a bucket of popcorn in her cage to share with Barrel and munch on when shit goes down - and it often goes down. She's the primary instigator of an ongoing running joke where the witches' niece, Agatha, crushes on Barrel, who is completely oblivious to it. Carver often gives bad advice to Agatha to "woo him over" while manipulating the situation (often with Shock's help) to ensure Barrel doesn't catch on. She taught Igor to pull the switch to create lightning for dramatic effect whenever Finklstein realizes whatever shenanigan she just pulled and screams her name in frustration. Having no sex organs or need for romance, Carver finds Sally's romance novels hilarious, and often because she takes them too literally. She can hold her own in a fight with any of the tricksters. She often finds flaws in their plans, and helps make them better. Carver also has decent rapport with some citizens, like Behemoth, who taught her the ins and outs of pumpkins, and Sally, to whom she can share gripes about trying to evade Finklestein. She does get frustrated with being considered an afterthought in comparison to her friends, though. Lock, Shock, and Barrel were the original pranksters, so while her friendship with them is acknowledged, a Halloween Town citizen is far more likely to blame one or all of them first for any mischief before they even consider her.
Carver's great. I fucking love her.
Of my characters (and let's be real here, I tend to cover most of the canons), it's Shock. Not even a contest.
Her base characterization is "bitch," which in and of makes her fun to play. In this version, she is the worst (non-evil: that has to be specified because there are a few characters who are legitimately evil in this game) person in all of Halloween Town, and due to it, is the second most-feared monster after Jack. Shock likes playing massive tricks, with the end result of making the victim(s) as miserable as she can - Jack can actually generally gauge which trickster was behind a trick based on this. Her latest brain child? Making all of Halloween Town think they missed Halloween. While it took her brothers' and Carver's assistance to pull it off, it's amazing what you can accomplish with a few forget-me-lots and some fog juice. She got entertainment for days watching other citizens meander and moan over "missing" the most important day of the year. Totally worth the punishment from Jack when he and Sally finally figured it out.
After Oogie's defeat, Shock asserted herself as the trio's leader and maintained that status as the trio grew up. It's telling that Barrel is physically bigger and stronger than her, but won't start a fight with her. That's because Shock doesn't rely solely on brute force to get her way: she's devious and clever too, and knows how to turn her younger brothers' strength against them to ensure her leadership status. She raises scorpions to sell (whole and in parts) to the witches' shop so she and her brothers have a source of income, and actually personally set the high standard regarding her products, because it would only take one ruined potion to ruin her business. Halloween Town generally has a saying: they trust her wares, but her, not so much. Shock also often has a trained scorpion to assist her in her mischief.
While Shock takes pride in her reputation as a bitch, she isn't heartless. Like most of Halloween Town, she'll help a monster in need, regardless of personal opinion. Of course, once the truce ends, she'll happily backstab if it suits her, so make a deal with her at your own risk. She also looks out for Lock and Barrel (and to some extent, Carver), sometimes to the point of her own detriment. She may not always openly show it, but she loves them more than anything, and will subtly (and sometimes not-so-subtly) manipulate a situation to ensure their overall happiness. Part of the reason she ensures she retains her leadership position is to ensure normalcy among the trio and to keep things fun even after Oogie's passing. She's also able to make difficult decisions Lock or Barrel may not have the stomach for.
One of the biggest plot points in the game is Lock, Shock, and Barrel are the only citizens who are actively growing and aging (Carver doesn't count; if not for her limb enhancements, she'd be in stasis like everyone else). All the other teens kind of appeared as the age they are, and stay there. There's a legitimate fear among the trio of reaching adulthood, because for most of their lives, they were young children, and now, suddenly, they're growing up and dealing with change when everyone else around them stands still. Being the oldest, Shock is going to reach adulthood first, and the thought legitimately terrifies her. Part of the reason she's controlling and insistent on retaining normalcy in the trio is because of this. She also recognizes how it affects her brothers: Lock is in a relationship, but the aging issue undertones it, because he may eventually out-grow his partner. Barrel is a lot more casual overall, but he's also the least responsible one, and being a teen still allows him to be somewhat carefree, whereas adulthood means responsibility. Being children for so long also screws them all up mentally, as they feel they should all still be little trick-or-treaters, and that the stasis they once had vs. them now growing up is a constant mental battle as they fight their more childlike urges for some semblance of maturity. Shock publicly appears to be the most collected of the three, as she utilizes her reputation to make Halloween Town think twice about messing with her - or her carefully crafted reality - and that everything she does is just a devious game to her. Truthfully, she's walking a tightrope without a net while balancing weights in either hand - and that tightrope gets thinner and more threadlike each day while the weights get heavier and heavier.