The game's full of 'em, particularly the "Squad 7 Dramas".
Any moment between Welkin and Alicia. Bonus points if they're alone.
Alicia: Once this war is all over... I have... there's something I want to tell you.
Welkin's proposal to Alicia after Chapter 16.
The ending, when they showed Alicia and Welkin's daughter, named Isara.
Selvaria's DLC. The realization that you'll have to fight and kill everyone of Selvaria's group makes you feel a little sad.
Unless you are evil and were hoping for a full campaign where you get to annihilate Squad 7.
Right before the militia march to attack the Marmota for the second time, there's a clip of the Aged Gentleman who's been teaching Welkin orders all game, because he knew his father in the last war:
Aged Gentleman: Belgen...If you're watching up there, your son could probably use a little help.
After mission 5-5, Captain Varrot congratulates Welkin on another successful mission, but Welkin tells the Captain that is was Hans, the piglet, who was to be credited for the victory(since thanks to him Welkin found the forest trail that allowed them to attack the base). Does Captain Varrot roll her eyes at such a silly gesture? Does she tell Welkin to stop joking? Nope, she welcomes Hans as the newest member of Squad 7 and tells him she expects many good things from him. Awwwwwe! :D
The Bielert brothers. The younger brother, Emile, is an Ill Boy who mustered the courage to enlist in the militia despite his poor physical condition. The older brother, Oscar, enlisted immediately afterwards to protect Emile.
Many times when a unit calls the medic upon reaching a downed comrade. Glimpses of many otherwise concealedhearts of gold can be had in the genuinely worried voices used when they're calling for the medivac.