Alku, one of the RPG's veterans, has recently begun telling his niece stories about happenings in RotR, to adorable results.
Suicune's egg hatching. After everything Kyle, Sonja, and the others had been through in Unova, it was refreshing to see a real glimmer of hope again.
The lead-up to this was also heartwarming, if a bit odd, as it demonstrated how much Kyle and Sonja care for each other—even being willing to go to some extreme lengths to ensure the other is okay.
Zach and Olivia reuniting, and their subsequent Relationship Upgrade. Both had begun to suffer negatively on an emotional level—Olivia due to being separated from Zach for so long, and Zach because of his failures in Unova leading to a massive Heroic B.S.O.D.. Now that they're together, Zach has begun to get back on his feet while Olivia has become kinder.
Similarly to the Zach and Olivia example, Evan expressing his feelings for Jenny and theirRelationship Upgrade. Evan's support has allowed Jenny to grow stronger and more capable of handling herself, while Jenny, in turn, has helped to rein in Evan's impulsiveness and any bad decisions he might end up making—not to mention, helping him keep his humanity, as shown in a Flash Back where he considered killing Gerald.
Ellen's relationships with several of her friends.
Evan, effectively Ellen's unofficial big brother. She was the primary one to stand up for him during times of trouble, and she received Maturin from him. Furthered by their brief memory sharing experience before the battle with the Ancients.
Sonja, at least for a time, acted as a sort of Cool Big Sister to her during the Unova Arc. A bit of a Tear Jerker considering that, having never gotten a chance to meet her own older sister before her alliance with Ford, Sonja could have been unconsciously acting on a broken impulse.
Richard comforting Zoe after Colette left for her initiation mission.
Sam and Will refusing to abandon Joker during Ford's attack on the Moreno Estate.
James reminiscing about Jamie's childhood stage.
Aspen rescuing Saya from the burning building in Sootopolis.
Likewise, his dedication in trying to locate Dahlia when she had been kidnapped by Alistair.
Dack and Madison's relationship, especially during the attack on Celadon, with both being deeply concerned about the other's safety.
Doubles as a Tear Jerker as well as a bit of Nightmare Fuel, considering what comes out after it, but seeing Jackson Sang's memories of his younger self and his relationship with his friend Emre. It's clear the two cared about each other a great deal.