77		Sid Meier's Alpha Centauri (Windows, 1999)
74		Deadlock: Planetary Conquest (Windows, 1996)
60		Holy Potatoes!: We're in Space?! (Windows, 2017)
54		Imperium Galactica II: Alliances (Windows, 2000)
52		Software Inc. (Windows, 2015)
50		Market Tycoon (Windows, 2017)
50		Wildlife Park (Windows, 2003)
50		Transports (Windows, 2018)
50		Production Line (Windows, 2017)
50		Coffee Shop Tycoon (Windows, 2016)
50		The Sims: Carnival - SnapCity (Windows, 2008)
50		Tavern Tycoon: Dragon's Hangover (Windows, 2017)
50		Wildlife Park: Gold Reloaded (Windows, 2018)
50		Gnomoria (Windows, 2013)
50		Terroir (Windows, 2017)
47		Caesar III (Windows, 1998)
47		Anno 1602: Creation of a New World (Windows, 1998)
46		The Settlers III (Windows, 1998)
46		SimCity 3000 (Windows, 1999)
46		Pharaoh (Windows, 1999)
45		The Settlers II: Veni, Vidi, Vici (DOS, 1996)
45		Serf City: Life is Feudal (DOS, 1995)
45		Zeus: Master of Olympus (Windows, 2000)
45		Sid Meier's Civilization III (Windows, 2001)
44		FireFly Studios' Stronghold (Windows, 2001)
44		Caesar II (DOS, 1995)
44		Tropico (Windows, 2001)
44		SimCity 3000 Unlimited (Windows, 2000)
43		Stronghold Crusader HD (Windows, 2012)
43		SimCity 2000 (Windows, 1996)
43		SimCity 2000 (DOS, 1993)
43		Caesar II (Windows, 1996)
42		Emperor: Rise of the Middle Kingdom (Windows, 2002)
42		Parkitect (Windows, 2016)
42		Stronghold HD (Windows, 2012)
42		Industry Giant II (Windows, 2002)
42		SimCity 4 (Windows, 2003)
42		FireFly Studios' Stronghold Crusader (Windows, 2002)
42		Zoo Tycoon (Windows, 2001)
41		Port Royale 2 (Windows, 2004)
41		Tropico 2: Pirate Cove (Windows, 2003)
41		Port Royale: Gold, Power and Pirates (Windows, 2003)
41		FireFly Studios' Stronghold Deluxe (Windows, 2002)
41		Offworld Trading Company (Windows, 2016)
41		Knights of Honor (Windows, 2005)
41		Train Valley (Windows, 2015)
41		The Settlers II: 10th Anniversary (Windows, 2006)
40		The Settlers: Rise of Cultures (Windows, 2008)
40		University Tycoon: 2019 (Windows, 2018)
40		Train Station Simulator (Windows, 2017)
40		Stronghold Crusader Extreme (Windows, 2008)
40		1849 (Windows, 2014)
40		Airport Tycoon 3 (Windows, 2003)
40		FireFly Studios' Stronghold 2 Deluxe (Windows, 2005)

Notes: Games similar to The 3rd Millennium, Games like The 3rd Millennium, Cryo Interactive Entertainment, Cryo Interactive Entertainment, Windows, Simulation, Strategy, Tactics, Sci-Fi, Futuristic, Managerial, Business Simulation, Bird's-eye view, Isometric, PC, Game Similarities.