OpenFracas is described as 'free, open-source game that is similar in style, but not in specifics, to Risk. On randomly generated and customizable maps, humans are pitted against other humans and AIs in an attempt to eliminate all other players or teams'. There are more than 25 games similar to OpenFracas for a variety of platforms, including Android, Windows, iPhone, iPad and Mac. The best alternative is The Battle for Wesnoth, which is both free and Open Source. Other OpenFracas like games are FreeCiv (Free, Open Source), TripleA (Free, Open Source), Domination (Free, Open Source) and Freeciv for Android (Free, Open Source).
Freeciv is an open-source, turn-based strategy game based on Civilization II. Inspired by the history of human civilization, the game commences in prehistory and your mission is to lead your tribe from the stone age to the space age...
TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game. A wide variety of map scenarios have been developed for TripleA (World War II, Punic Wars, Napoleonic wars, etc.
UniWar is a turn-based strategy game where players battle it out on the field with units of differents races, building bases and using the terrain to overcome their opponents towards victory. Several modes are available along with many maps to play.
Advanced Strategic Command is a free, turn based strategy game. It is designed in the tradition of the Battle Isle series from Bluebyte. ASC can be played both against the AI and against other human players, using hotseat or PlayByMail.