Particlescape - Particlescape app lets you create stunning patterns at your fingertips.
FreeCiv - Freeciv is an open-source, turn-based strategy game based on Civilization II.
TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.
C-evo - C-evo is a freeware empire building game for Windows
Fluid dynamics - Fluid dynamics developed and published by Reinder Nijhoff.
Sid Meier’s Civilization VI - Sid Meier’s Civilization VI is a Turn-based Strategy, War, Tactical, Single and Multiplayer video game created by Firaxis and published by 2K.