Favorites of the decade:
Europa Universalis IV (PC, 2013)
Civilization V (PC, 2010)
Crusader Kings II (PC, 2012)
The Witcher III: Wild Hunt (Multi, 2015)
DOTA 2 (PC, 2013)
Divinity: Original Sin II (Multi, 2017)
XCOM 2: War of the Chosen (Multi, 2016)
Fallout: New Vegas (Multi, 2010)
Fire Emblem: Three Houses (Switch, 2019)
Total War: Shogun II (PC, 2011)
My all-time list is going to involve a lot of stuff from the 90's and even the 80's. It's not that I'm some kind of retro gaming hipster, I'm just old.
Baldur's Gate 2: Shadows of Amn (PC, 2000)
Deus Ex (PC, 2000)
Mega Man 2 (NES, 1988)
Final Fantasy VI (SNES, 1994)
Castlevania: Symphony of the Night (PSX, 1997)
Rome: Total War (PC, 2004)
Chrono Trigger (SNES, 1995)
Ultima VII: the Black Gate (PC, 1992)
Starcraft (PC, 1998)
Unreal Tournament (PC, 1999)
Betrayal at Krondor (PC, 1993)
Crystalis (NES, 1990)
Final Fantasy Tactics (PSX, 1997)
Dragon Force (Saturn, 1996)
One Must Fall: 2097 (PC, 1994)
Europa Universalis IV (PC, 2013)
Star Wars: Knights of the Old Republic (PC, 2003)
Civilization V (PC, 2010)
Dragon Age: Origins (PC, 2009)
Crusader Kings II (PC, 2012)