On my first playthrough:
1.) Freed the tree spirit. Baron hung himself after his wife died.
2.) Killed Whoreson.
3.) Helped Keira. She was present during the battle of Kaer Morhen then left with Lambert. Later, she cured the plague.
4.) Helped the mages escape Novigrad and said goodbye to Triss.
5.) Cerys became queen of Skellige.
6.) Assassinated Radovid.
7.) Sided with Roche and Thaler to kill Dijkstra, resulting in the empire's victory in the war.
8.) Ciri became a witcher.
9.) Geralt retired with Yennefer.