The 97's endings of The Psycho Soldier Team and The Women's Team are both so, so cute. Specially when Athena teleports to help Ill Girl Kaoru when she tries to walk and falls off her wheelchair and when Chizuru hears her dead sister Maki's voice in her mind, telling her to be happy. (The second might be Harsher in Hindsight, tho, considering what happens to Chizuru and Maki in 2003.)
The Fatal Fury Team's 2000 ending. Terry has apparently died after the last fight and the destruction of Sotuh Town, and Mary narrates what has been going on in a rather melancholic tone. At the end, however, she steps in a warehouse where she's supposed to find some burglars, they're already beaten up... and the one who did it was Terry, who stands in the doorway and smiles.
Even if they're non-canonical, Kula's Sky Stage endings are rather sweet. Specially her solo end and the ones she shares with Kyo and Athena.
In the KOF 94 manga by Tatsuya Shinjyouji, two moments stand out:
The first volume gives us Jan retrieving King's discarded KOF invitation letter and telling her to stop sacrificing her happiness for him and her business. This leads King to accept Mai and Yuri's offer to team up with them.