Miyuki is the best big sister ever. Her advice to Nanoha, and teaching her how to fight with a staff to enable Nanoha to protect herself, goes a long way to show how much she cares about her.
Fate taking care of Nanoha after the dimensional quake, even though they were still enemies at that point.
In chapter six, when Fate comforts Nanoha, who is distraught over being separated from her family.
Later in the same chapter, Nanoha's conversation with her mother is very touching.
And then there's Fate bringing Vesta to Nanoha so that she wouldn't feel so lonely.
Vesta's devotion to Nanoha is also pretty heartwarming.
In chapter eleven, Precia actually hugs Fate, which very powerfully demonstrates just how different she is from her canon counterpart.
Also from that chapter, Vesta's conversation with Linith is pretty touching.
Chapter eleven in just full of these. The scene with Megane and newborn baby Lutecia, and the one with Tiida and Rizu playing with Teana are both very "dawww" inducing.
At the climax of the story, Nanoha once more chooses Fate over Yuuno, and accompanies Precia into Imaginary Space, which is both this and a Tear Jerker.
I'll see you again someday, and make things right. I promise.
In the epilogue, Alicia is successfully revived.Squee!
Nanoha's reunion with her family in the second chapter of Power Games.
In the third chapter of Power Games, Vita recites a love poem to Hayate.
Mei revealing how she turned her life around in the fourth chapter of Power Games. As Quint says:
You know what? Thatís the best thing Iíve heard since the damn Jewel Seed Incident started
Chapter 6 of Power Games: Yuuno protecting Nanoha. He knew he'd probably get in trouble for it and it seems like he was at the very least chastised for not trying to convince her to come back to the TSAB in the last chapter.