Wrex: He could only wish, resentfully upon a still distant star, to one day have a son like her.
Shepard: "I never had a brother. But if I did, I wish he were you."
Shepard’s talk with Karin while Garrus was in a coma.
When Garrus woke up, he was greeted by Karin. Even when the scene seemed so ordinary, there was something so heartwarming about how Karin acted so motherly with her teasing and caring way.
After she returned from Alchera, Shepard and Garrus finally (wordlessly) acknowledge their feeling for each other.
And they both knew, they would never. Ever. Leave each other. Again.
That moment gets sour after that when Garrus’s sense of guilt comes to him, and he hides himself in the battery for 2 months, not saying a word to Shepard. Good thing Thane came to the rescue and talked him out of it.
Chapter 28: Garrus and Shepard finally consummate their love.
Nihlus saved a young Shepard and was willing to fight against Samara to protect her.