The Secret History by Donna Tartt, the bit when Richard is hospitalized and Henry stays with him and looks after him and Richard writes (from memory):
"Of course Henry is dead now, but I like to think that somewhere there's a gold star by his name."
"Searching For Shona, children's book about two girls evacuated in Ww2 from Edinburgh. Ending is shocking and sad.
"What falls away" by Jay McInerny when Jeff dies of AIDs.
"Restoration" no majorly sad bits but just poignant throughout. The bit about having a tabard made for the King made me so sad.
"Year of Wonders" when the children die of plague. Happy and totally -unrealistic ending.
Year of Magical Thinking, Joan Didion about the year after her beloved husband died.
City of Thieves by David Banioff when the aspiring writer who has been so overly-confident throughout gets shot and dies.
I don't know how she does it by Allison Pearson, the bit where the mother who is dying writes a long "family manual" for her husband, entitled, "Your Family. How it works" and her funeral scene.