Once she lets the mask drop a little, Archmage Twilight's reaction towards Princess Luna is as likely to bring out a warm glow as it is to draw tears. Twilight is genuinely happy to see Luna again, like she were reuniting with "her" Luna - as Twilight herself almost puts it, before hastily retracting herself. There really is no malice in the Imperial Twilight's initial interaction, and it isn't until Luna makes it clear they have to be enemies in this war, with great reluctance on her own part, that Twilight opts to draw blood.
Chapter Nineteen - "When The Dust Settles"
Verity Carter's appearance and conversation with Princess Cadance, following the battle, is seemingly made to evoke Moments of Heartwarming at every turn. The only known living human-to-pony convert who's kept her personality, to the point she's considered by many an in-universe to be an Urban Legend, but it doesn't stop there; Verity is a reformed member of the HLF, the daughter of its founder in fact, and she's made her peace with her situation, albeit not after much inner struggle. She and Cadance find some common ground, too, in that they were both adopted.
How does Verity opt to demonstrate for Cadance that she's adapted to being a pony? By inviting in her Second Love, Dearheart, to help her show off a very pony-style three-times hip-bump. Worth noting that Dearheart is at first a little embarrassed to do this in front of a Princess, but agrees to because it's Verity.
For readers of the original The Other Side of The Spectrum, the return of Verity likely counts as a Moment of Heartwarming in itself, after her arc was left unresolved post-cancellation. This also is the character's first appearance in a Spectrum main story.
Chapter Twenty-One - "Nostalgia"
All of Lady Cadenza's interactions in this chapter, rekindling bonds with Prince Blueblood, hearing of her family history from Princess Luna, or giving Lyra a pep-talk, can count.
Chapter Twenty-Five - "Family"
Princess Celestia's family photo-shoot has been cited by readers as a genuinely heartwarming moment. In a last moment's respite before returning to the concern of the looming war, Celestia gathers all of her living family together, old and new, to share in a get-together and have their picture taken as one.
And while there is a tearjerker element to it, Celestia privately remembers Sunset Shimmer in fond terms, indicating she still holds onto a hope at reconciliation. Her last thoughts during the photo-shoot scene show Celestia outright contemplating what it'd be like to have Sunset in the picture, as it were.
