Heartwarming / The Return to Gravity Falls

• Despite everything that has happened to them in the time since they left Gravity Falls, when the call comes in that Stan died, the twins instantly drop everything to go to town. Then, after Stan's body disappears, they, along with Soos and Wendy, work together to solve the mystery, just like old times.
• Dipper admits that he was upset about Mabel and Stan saying she was stronger than him because of the Paths training. Mabel tells him that he doesn't need to prove anything to them and offers to train him in turn.
• Despite him only knowing the twins for a few hours, and being wary of humans in general before hand, Yuki defends them against his father, helps them escape, and fights a tiger-like alien that is about to kill Dipper, all to bring back the citizens of Gravity Falls. The twins then defend him against Stan and make him agree to take Yuki in, which is helped by them deciding to stay in town for the rest of the summer.
• Stan telling the twins to knock 'em dead before they perform in the talent show, not just so he can make money, but also because he wants them to succeed. He even offers to look for the Warlock when it's time for the twins to go on. Really, any time Stan shows that he cares more about the kids than making money is this.
• After Dipper brings Mabel back to normal from being a werewolf, they give each other an awkward-sibling hug and tell each other that they love the other.
• Mina and Waddles together in Mammoth Problems is flat out adorable. Period. Other moments in that episode include Pacifica giving Yuki a tour of the carnival and comforting him when he gets freaked out by the mirror maze, as well as Dipper and Pacifica making up after they broke up three years ago.
• As said before, any time Stan shows that he cares more about the twins than money is great, and it shows when, after the Warlock's attack on the business convention, he puts his foot down and tells the twins that they can't go adventuring anymore unless they know for sure what they are up against, or everyone, himself included, is together.
• Even though they barely know each other, Zander is able and willing to help Dipper after he and Mabel get in a fight, easily making Dipper see sense.
• Several moments in both Summerween Carol and Summerween Returns, starting with Stan feeling bad for Dipper being upset about Wendy keeping secrets, but also knowing full well that it's not his place to spill Wendy's secrets, no matter how much he might want to help his nephew.
  • We then see Yuki refusing to badmouth Stan despite the twins telling him no one would judge him if he did so, Yuki being nearly as loyal to Stan as Soos is, despite their differing perspectives on life. (And we later see that Stan returns the sentiment.)
  • A small moment is seeing Zander and Pacifica shopping for Summerween party supplies, Zander having taken Pacifica in after her parents kicked her out following the phoenix incident.
  • Stan admits to Arline that he was jealous of her relationship with the twins, but Arline assures him that he will always be more important to them than she ever will be.
  • After he and Mabel find out Wendy is a wraith, Dipper figures out a way for her to still have fun on Summeerween- move Zander's party to the graveyard and dance with her so no one will freak out when they see her. It works so well that she kisses him before disappearing into the woods.
• The relationship between Yuki and Pacifica is all kind of heartwarming, especially when they go on their first official date with Mabel following the entire time to encourage a nervous Yuki, who really doesn't want to mess anything up. It ends with Yuki admitting that he's an alien and the two kissing when Pacifica assures him she doesn't care about that, or the considerable age difference between them.
• As depressing as the entire situation around it is, the fact that Dipper is willing to give up the Journal to fix Wendy shows just how much she means to him.
• Even though the results are disastrous, the fact that Yuki defends Dipper from the Warlock's blackflame despite being kicked out of the Manor the day before speaks volumes about how quickly Yuki became part of the Manor family.
• Fires of Hate and the first part of Broken Earth and equal parts this and tearjerking, as all three chapters deal with the aftermath of Yuki's sacrifice. There's several arguments throughout, but in the end, the family comes together and helps each other through their pain, getting everyone ready to fight again. Mabel said it best:
  "When your family is torn apart because of monsters [...] and you still get by because you remember what you saved? That's real strength! [...] When we still lose and we lose bad, but we get back up and keep going, and we don't quit on our friends."
  • The best part is that the second round of battles is not even about revenge like the first ones were; now it's just about making sure those responsible don't do any more damage.
• While Omir is technically a villain, two moments show that, unlike his apprentice, he is not a bad person. The first moment is when he offers, then follows through, on using a spell to fix Yuki in a matter of hours as opposed to the 80-so years Yuki said it would take. Then, after entering a BSOD following the discovery that Bill tricked him, Omir starts working alongside Arline and Stan as they feed energy into the Portal in an attempt to stop it from destroying reality. Omir truly was just a pawn in Bill's scheme, and he starts working against Bill the second he can.
• Soos' Undying Loyalty to Stan is never shown more fully than when he obeys his boss' last order to get Wendy and the twins out of town. Soos attempts one sentence to get Stan to not play hero, but as soon as Stan gives Soos the keys to his car and gives the order to protect himself and the kids, Soos does everything in his power to get Wendy and the twins ready to leave, including yelling and cutting Wendy off when she tries to say they need to go back downstairs.
• The first episode of season 3 easily could have been a narmy, cliche mess with Mabel helping a werewolf and vampire get together, but it ends up heartwarming because it is the first heartwarming moment in a long while that is not surrounded by pain and death. Readers greatly enjoyed a light-hearted love story after everything dark that happened in the back half of Season Two.
• Edward the Chupacabra being honest with his mother and Dr. Moriau accepting Edward how he is, the two of them agreeing to go back to being mother and son instead of doctor/scientist and patient/experiment.
• While opinions on the Guardsman are varied both in and out of universe, not even Dipper can turn him down when he insists on checking on his students after their bus crashes.
• The second part of Spectral Revelations, which culminates the four-chapter arc into an epic power of family speech by Dipper, a speech that rivals his testimony in Escape From Reality in the level of heartwarming it reaches.
• Even ignoring the fact that Soos and Melody are together despite it being an alternate timeline, Melody calling Soos her superhero and encouraging him to save the world despite it being crazy dangerous and both of them being terrified about what will happen is this. And while it never happens because the alternate timeline get erased, Soos proposes to Melody and she says yes.
• After about ten episodes of secret keeping and anxiety, Dipper tells Mabel about his secretly using magic, and while they do fight about it, it's not an emotional fight. Both twins are very logical about their arguments and treat the issue like adults, listening to each other and eventually agreeing that Dipper can use magic in emergency situations without Mabel being upset at him for it.