Hay day - Farm with friends and family
OpenTTD - An open-source clone of the classic game ...
FarmVille - FarmVille lets players cultivate their farms by plowing, planting and harvesting crops and trees.
Micropolis - Micropolis is the open source version of SimCity Classic from Maxis, developed by Will Wright and Don Hopkins.
Farm Up - Farm Up is a marvelous, Action, Farming, Social Interaction, Single, and Multiplayer Simulation created and published by Realore.
Simutrans - Simutrans is an open-source transport simulator.