This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Vinland Saga
The death of Ragnar and Prince Canute's dream after his father figure is killed.
Never mind Thors being cruelly murdered in front of his young son, pleading for the lives of the boys he had taken with him, then Ari desperately trying to avenge him as tears stream from his eyes, only to be smacked down by Askeladd. Askeladd's entire crew being slaughtered by Thorkell's men. Ylfa, struggling to take care of her mother after both her father and brother are gone, Thorfinn presumed dead, Thors murdered, and only breaking down into tears after several months of hard living, keeping up a tough front for her mother's sake. The English woman watching in disbelief as Thorfinn's countrymen sack her village, after she had saved his life and treated him as if he were her own son, Thorfinn begging her to run for her life as she just stands there staring at him. The girl found in the snow, holding onto the ring she stole, after fleeing the slaughter of her entire family. Bjorn, dying in Askeladd's arms. The slave dying after Thors had tried his hardest to keep the man alive. Askeladd's mother telling him the story of King Arthur and Avalon, then showing him carrying her as she was dying, returning her to Wales after living as a slave for years. The whole story is one great tearjerker, and it isn't even finished yet!
Thors' death, then Ragnar's death, then Askeladd's men betraying him, then Atli's brother going through a major BSOD, his mind reduced to that of a child's. But the most heart breaking moment would be Bjorn's death. Indeed he was Askeladd's one true friend.
Askeladd carrying his dying mother, a slave taken in a Viking raid, back to her home in Wales. Made all the more so by the fact that up until this point the readers had been lead to believe Askeladd was nothing more than an amoral bastard out for himself.
Askeladd getting stabbed by Canute, right in front of Thorfinn. Thorfinn loses it when he realized Askeladd had essentially become his surrogate father, and he simultaneously wanted to save his life and kill Askeladd himself. Made worse by the fact that Askeladd was stabbed right after telling Thorfinn to stay away. Essentialy making Thorfinn think that Askeladd cared for him in the end and that his distraction caused his death by Canute's hands.
Seeing that Canute ultimately could not overcome the power of the crown.
Arneis's backstory. She lost her home, family and freedom for "pots and pans". (The men of her village all went off to battle over an iron mine and her village was attacked by raiders in their absence, forcing her into slavery.)
Gardar using his final breaths to talk to Arneis about how he's going to be a good father to Hjalti, not realizing that their son is dead or that he's dying.
Arneis is brutally beaten by Ketil for trying to escape, even though she's pregnant with Ketil's baby. She dies of her injuries as a free woman since she is bought and freed at the same time as Thorfinn. The baby dies too.
Einar wanting revenge for what happened to Arneis. Thornfinn manages to talk himout of it, knowing firsthand the pain and suffering caused by one's thirst for revenge. Einar ends up collapsed on all fours, crying. Thorfinn, understanding Einar's anguish and grieving for Arneis himself, holds onto Einar and weeps into his back.
Thorfinn's return home and his reunion with his mother counts as a happy Tearjerker as his fears that his own mother wouldn't recognize him are quashed and with tears in her eyes, she says that he looks just like Thors. He breaks down in tears as he apologizes for being a bad son to her and she clearly forgives him. After years of pain and misery, Thorfinn is finally home with his family.