Teela ascends to her father's position as Man-At-Arms. And Duncan couldn't be any prouder.
While Teela initially refused to help the Sorceress reforge the Sword of Power, it was Cringer who convinced her to help, not by admonishing her, but by empathizing with her. He's a Cowardly Lion, he knows fear, and recognizes that Teela's afraid right now; Afraid of the responsibility of saving the world and afraid of letting Adam down by failing that responsibility. Teela shot back that Cringer knew Adam better for knowing his Secret Identity, but Cringer again is understanding by pointing out how close Adam and Teela were. He even points out that one of the reasons Adam was able to make his Heroic Sacrifice was because he had faith in Teela that she could protect Eternia in his absence.
Beast Man's chivalrous relationship with Evil-Lyn. His deep fondness for her is obvious and he always has her back, ready to defend her from any and all threats at a moment's notice. His protection is quite welcome, too, since Eternia's dying magic has predictably left Evil-Lyn's sorcery in a severely weakened state.
Roboto's relationship with Duncan and Teela. There's no question that he considers them his surrogate father and sister. Which makes his Heroic Sacrifice all the more heartbreaking.
Then there's Roboto's sacrifice itself. He did the right thing, as otherwise the heroes would have ultimately failed, but like He-Man before him, Roboto ends up dying for the good of the universe. In his final moments, Roboto admits that he's scared out of his wits, yet seems almost... thankful to be gripped in fear. Because if he can feel fear, he argues, then that proves he was alive. And if he was alive, then he wasn't a machine... but a miracle.
Evil-Lyn urging Orko to see his own self-worth, after learning that he was a talentless loser on his home world (especially in the eyes of his parents). Think about this. Other than the Sorceress, Orko was the only member of He-Man's team who used magic (and he rarely if ever impressed them with his spells). With her own talent for magic, Evil-Lyn was able to connect with Orko in a way his old comrades never could, and make him realize his true power. Tragically, Orko sacrifices himself soon afterwards... but he goes out with such a display of magic, his parents would have finally been proud.
Adam has found genuine friends in the heroes of Preternia, and even their teasing him about taking his lesser form comes off as good-natured. Later, they are genuinely worried when he decides to leave, but respect his decision.
After making a grave for Orko, Adam asks Moss Man (now part of the forest) to give Orko a "little bit of home". Moss-Man obliges, transforming the soil around Orko's grave into an alien patch of Trollan grassland.
Adam's reunion with Cringer. The latter might be a big cat, but he has all the affection and loyalty of a noble hound.
King Randor can still recognize his son even after his son has been turned into a hulking wild man by the un-tempered power of Grayskull. When he sees Adam being restrained by his army, he immediately tells everyone to lay down their arms and proceeds to give Adam a long-overdue apology for the way that he's treated him and tells him that he's proud of him. He ends up being the one to return Adam to normal via a Cooldown Hug.
In a flashback, Skeletor, seeming to have just arrived on Eternia, saves Evil-Lyn from the pursuers she stole from. While he's sadly lost any care for her in the present, Evil-Lyn admits flat-out she owed Skeletor her life.
A possible heartwarming moment: When Evil-Lyn kills Panthor, Skeletor seems enraged by it, implying he might have cared for Panthor. While it may have just been frustration, it's also possible that Skeletor of all people genuinely gave a damn about his pet.
After Adam gets the sword again, he gives Skeletor his Skelegod powers back. Skeletor is confused by this, so He-Man tells him that he wants Skeletor to know what saving the universe is like. Unfortunately, this bites Adam back when Skeletor turns on him again.
Evil-Lyn is defeated in the end not by destroying her or even beating her into submission but by Teela showing her the birth of Eternia, revealing that while the universe is chaotic and cruel, it is also beautiful.
Teela: You're right. The universe, it's chaos, it's hurt and death. But it is everything else, too. It's beauty. It's love. It's life. The universe, it's... Evil-Lyn:(breathless with awe)It's magic.
When the zombies are sent back to Subternia, that includes Orko... Thankfully, Evil-Lyn uses her last dregs of Power to ressurect him for good.
Evil-Lyn: Not this time.
When Orko first came back, he was actually able to properly cast magic and was able to hold his own against Evil-Lyn. It's implied he was holding back because he saw that there was good in Lyn. Not only was he right, his mercy got rewarded with a second chance at life.
