Jossed: Turns out, Cadance wasn't born an alicorn, and was became one after using her own love to stop Lady Prisma from stealing a nameless village's love. In this story, Cadance has always been an alicorn for several hundred years, but now integrates the canon by having that moment be when Celestia learns about Cadance's existence.
Tear Jerker: Princess Ladybird's Death by Childbirth. Ladybird lived a long life of suffering from her love, but has had her kingdom brought to ruin and her death rapidly approaching, finally giving in to despair as her closest friend desperately tries to reignite hope in her. Finally, she ends up giving birth to her daughter, never being able to see the mare she'll grow into, and her legacy and her empire lost to time. Auric Turncoat gets it as well, losing his only friend who understands his situation and blaming himself for his death. He's literally bawling as he sadly asks to see Cadance, all that is left of Ladybird.