Here's the optional rules we're using:
Variant Strategy Cards
Strategy cards in Twilight Imperium determine turn order and also determine what special abilities a player can have access to during that round, whether it?s getting a free technology, additional command counters or allowing the exchange of trade agreements. For this game we went with the alternate set of Strategy Cards offered in Shattered Empire that offer similar but different options for players than the main set; The Technology II card allows players to purchase multiple technologies at once when activated, for example, and the Warfare II card grants its user a special token that offers bonuses to movement and combat rolls.
Sabotage Runs
One of the deadliest units players can build in Twilight Imperium are War Suns; giant death spheres capable dealing significant damage to enemy forces just on their own. Sabotage runs essentially let players attempt to destroy an enemy war sun by sending a contingent of fighters in before a space battle and rolling to see if they can destroy it ahead of time.
Race Specific Technologies
The Shattered Empire expansion for Imperium introduced faction-specific technologies that races could research to give themselves an advantage that other players wouldn?t be able to duplicate, although they are far more costly to acquire. For example, the Federation of Sol can pick up advanced carriers, allowing them to build transports that are harder to kill and carry more units, while the Xxcha Kingdom can gain the ability to cancel enemy actions once per round.
Shock Troops
Shock Troops are special ground troops that you can earn whenever you roll a natural 10 during a ground battle, and are capable of capturing planetary defense systems and space docks when you invade a planet. They also have a much better attack value, but unfortunately they also must be taken as casualties first after a round of ground combat and revert back to being a regular ground force if they?re ever left alone.
Mechanized Units
Mechanized units are a more expensive ground unit that comes with more firepower and survivability than your normal Ground Force unit. While ground forces can only take one hit, Mechanized Units can survive two before being destroyed, and roll two dice when they attack.
The Wormhole Nexus
Wormholes can play a very strategic role in Twilight Imperium, and the Wormhole Nexus option can increase the value of using interstellar phenomena providing a planet that?s only accessible via a wormhole but contains access points for any other wormhole that can appear in the galactic map.
Tactical Retreats
Space battles don?t always work out the way you?d like them to go in Twilight Imperium, so naturally you have the option to withdraw your forces. However, in the base game, you can only flee into systems you?ve already activated in a turn, so if your first action is to attack an enemy player, you?re essentially dooming your fleet. Tactical retreats allow you to spend one of your few command tokens a turn to retreat your forces to a nearby empty system instead, allowing you to save some of your ships at the risk of possibly blocking off a region of space you may need to use later that round.
Mecatol Rex Custodians
Metcatol Rex, as the central planet in the galaxy and most often the goal of various objectives, is an undefended, easily conquered world in the base game. The Custodian option gives it a token defensive fleet of fighters and ground forces, making players have to invest a little more in the forces they send to claim it.
Flagships
The Flagship option gives each race their own unique flagship; a hulking, very expensive unit that often brings considerable firepower to a space battle or other special abilities into play. The Jol-Nar flag ship, for example, counts any dice that roll at 10 in combat as providing three hits instead of one, while the Brotherhood of Yin?s flagship allows you to use any nearby ground forces as fighters in space battles.
Distant Suns
Distant Suns adds more of a risky element to planetary colonization in Imperium; after the galaxy map is created, players randomly distribute tokens face down on every uninhabited world that triggers an event when players land ground forces on that planet. From free trade goods and technologies to hostile natives and virulent plagues, the Distant Suns option forces players to expand into the universe a little more cautiously.
The Final Frontier
Similar to Distant Suns option, Final Frontier tokens are placed in empty space and contain potential bonuses or hazards when surveyed. Players can find abandoned trade ships, survive pirate attacks or accidentally set off a supernova when using these tokens.