Games like Master of Orion 3. 20 Similar Games.

1. Master of Orion. (1993) 
2. Master of Orion 2. (1996) 
3. Galactic Civilizations. (2003)
4. Space Empires 4. (2000)
5. Endless Space. (2012)
6. Lost Empire. (2007)
7. Ascendancy. (1995)
8. Distant Worlds. (2010)
9. Star Wars: Rebellion. (1998)
10. Sins of a Solar Empire. (2008) 
11. Nexus: The Jupiter Incident. (2004)  
12. Armada 2526. (2009)
13. Haegemonia: Legions of Iron. (2002)
14. Sword of the Stars. (2006)
15. Star Wars: Empire at War. (2007) 
16. Imperium Galactica 2. (2000)
17. Star Trek: Birth of the Federation. (1999)
18. Pax Imperia: Eminent Domain. (1997)
19. Sid Meier's Alpha Centauri. (1999) 
20. Endless Legend. (2014)