This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Ghost, Ghost, I Know You Live Within Me
Shepard goes to visit her mother and her friends but no one can see or hear her.
The Archangel team's deaths...
Butler's face had been burned away. Sensat died with his eyes wide open. Monteague, in his dying breath, tried to drag himself to reach for Ripper. Vortash hold onto Mierin's body in his arm while he himself is dying. Erash was torn apart by varren's claws. Grundan's eyes was taken and his throat was cut. Even worse when you know how the eyes are treated in batarian's culture. Melanis's hands and jaw were broken. She died, suffocated by her own blood. Weaver tried to hide underneath the workbench after she was shot. She died in Garrus's arms, not before revealed her first name to him. It's Anna.
And Garrus had to go through on that, calling his friends' names each time he found one...