The end of the episode "Bad Feng Shui" in which Jessica fights back against the dark Chinese spirits who kidnapped her mother by playing her violin — as her mom loved her violin playing. Also the part where she buys a horse from Mr. Ling's store, as the horse is a sign of perseverance and she says that her mom would never give up on her, so she won't give up rescuing her mom.
The ending of "A Creature Was Stirring". The Krampus burns the family's house to the ground, but everyone survives, and the disaster causes the parents to cancel their divorce, as their kids need them now more than ever. As Timmy puts it, "This is the best Christmas ever." Quickly turned into a Crowning Moment of Funny when it's revealed that Santa Claus — riding in a stretch limo blaring Christmas hip-hop — is the one who brought the Krampus to Timmy's family because Timmy wished for something to bring his family together, and what better gift to give a strained family than a Christmas-wrecking demon.
The ending of "Pool Shark" where Kai learns that he and his father are really Nanaue (a mythological Hawaiian creature that's a man on land and a shark in the water). Kai comes to terms with this, and wins Alexa's heart by taking her on a ride through the water. Alexa is completely unafraid of his transformation.
The Reveal in Spaceman. The main character, Aaron finds out the "alien" he's been talking to was the ghost of a little boy, who loved playing as an astronaut, and whose mother kept him in the attic because she was so broken over his death that she didn't want to let him go. Aaron decides to keep the boy company, knowing he's interested in space as much as he is.
The Intruders. Eve chooses her adopted parents and baby brother over living with the Fae even if it means giving up her powers and earning the Fae's wrath. She even warms up to her baby brother, who she's resented the entire episode, managing to stop his crying when his parents couldn't. It helps that the parents in this episode are good people and they've really been trying to make an effort with Eve despite her constant attitude. Particularly there's this speech from Eve's father:
Eve's Dad: "I'm sad. Sad that you're so far away from me, from your mother... Eve, I want you to know that, no matter what you say, no matter what you do, we will always be your family. This will always be your home. You'll always be welcomed with love... I miss you, that's all. I love you kiddo."
In Really You: Lilly's mom—not knowing that Lilly D. and the real Lilly have switched places—is about to dump her real daughter into the trash bin. She notices that the doll has a mole on the back of its neck like her daughter. It's enough to make her realize what she's done and to bring Lilly back to her normal self. The two reunite in a hug.
Flight. Josh's talk with Vincent, who's a ghost, into going into the afterlife and their final goodbyes.
"Detention": Audrey talking Kate out of going to Hell and apologizing for causing the parade accident that killed Kate, herself, and a jock nicknamed Halftime, which got them stuck in limbo.
"Terrible Love": Stuart comforting Maggie days after she witnessed Brendon fall down the stairs (after Cupid made it so that way Brendon's love-induced rampage would end) — at least until it's revealed that Stuart set her up to be shot by Cupid.
Dead Bodies has Will and Anna being reunited after defeating Jake, and, earlier, Will looking after Anna despite that he's a ghost and Anna thinks Will either died or went missing.
Bad Egg: Despite admitting his latest mistake to his father, Jason is still sentenced to go to military school by his father. As Jason is packing, the furry monster that Jason tried to hide from his father and the government agents, only to escape comes back and Jason decides to take the monster with him to military school. Much like "Terrible Love"'s ending, it's sweet...in a very sick way.
"Toy Train": The switchman giving his life to save Logan's father from getting run over by the train and coming back to tell Logan's father not to be so hard on himself and his son because it wasn't anyone's fault that the switchman died; it just happened.
Holden going through with the guitar duel, knowing that he doesn't stand a chance against Sir Maestro (since Sir Maestro played professionally in the past and, since he steals the souls of musicians, probably has their talent as well), to save his friends in "Long Live Rock and Roll."
If you can ignore how weird, creepy, and almost sarcastic it comes off as, Uncle Howee and Loomis the rabbit telling Cynthia that they're her friends (and the duo breaking out of the TV to teach her jerkass brother a lesson) on the episode "Uncle Howee" is very sweet.
"Grandpa's Glasses": Bo discovers that the spirit of his grandfather has been locked in a room and that the demon haunting the house is the spiritual manifestation of his mother Carolyn's anger (who never forgave her father for leaving her as a child) and is going to burn the house down if Bo's mother doesn't forgive him. The heartwarming moment comes when he discovers that his grandfather had a picture of his daughter (Bo's mother) while he was traveling the world; this picture becomes the key in stopping the demon and letting Bo's grandfather finally rest in peace.
Once Carolyn finally lets go of her anger, the demon is restored to its true form: the sweet, kind girl in the picture. She shares a heartwarming reunion with her father, and it is implied that she is the one who takes him to the afterlife.
Missy actually being nice to the hired help and the homeless people her family encounters on the streets in "Goodwill Toward Men."