The popularity and growth of the "souls-like" genre over the past decade has been the highlight for me. Between FromSoft's titles (yeah yeah, Demon's Souls is from 2009), Nioh, Salt & Sanctuary, Code Vein, and even The Surge; it's been awesome to experience.
Seeing the Resident Evil series turn in a different direction from where it was heading with RE6 has been nice too. The Revelations games and RE7 were great. Also the Evil Within series, which took obvious influence from it (EW2 being the standout title for me).
It's been a great decade for other horror games as well. Amnesia, Outlast, SOMA, Little Nightmares, and LIMBO/INSIDE were nice entries in the non-combat horror genre.
Hollow Knight
Witcher 3
Fallout NV, Skyrim, and Fallout 4
Divinity 2
Binding of Isaac, and the rebirth of the roguelike genre
Deus Ex: HR
Far Cry 3
Life is Strange
MGSV
The Metro games
Portal 2
Wolfenstein: TNO