The first 'expansion' consisted of 5 cards, handed out at GenCon 2002.
You received these after answering some questions. The cards are virtually unfindable now.
Afterwards, 4 official expansions were released by Wizards of the Coast, as part of the Frontline program.
Game shops could organize in-store tournaments where players could win these expansions. The Frontline program is discontinued for a few years now and the expansions are officially not for sale. If you still want to play them, you can always check on ebay, or make them yourself.
Major promo cards
Jason Taylor - the Risk 2210 A.D. (and Major promo cards) art director.
An intern at AH. He did not like the name Flowers, so it was "Germanized".
Mike Gray (designer of Shogun and many other MB games) was the boss of AH. Luckily he saw the fun in being a "Major Pain".
Mars 2210 A.D.
The first expansion was the usage of an alternate game board. Here a view of the expansion called Mars. It consists of a new map (including new territory cards) and a new double moon.
Obviously, there are also new territory cards. We find several philosophers on the moons and SF writers on the water territories. Also a funny link to the Magic past of Wizards of the Coast (the mother company) can be found on some territories. This expansion opens up the game a lot, due to use of neutral territories.
The second expansion adds an extra commander to the game: the Tech Commander. The new commander also receives his own deck of Tech command cards.
This is an interesting expansion. The game sometimes gets an unexpected twist due to the use of the Tech command cards.
There are no Tech Commander figures included, just carton cutouts. You can always use different figures as Tech Commander, or create a Tech Commander using a 3D printer. (see links & downloads for the model used by Belgium2210).
The third expansion are the so-called Factions. This expansion adds more variation to the game by choosing (or receiving) a certain faction at the start of the game. Each faction has its advantage and disadvantage. The Tech Commander (expansion 2) is also needed, but can be replaced by the Diplomat Commander if needed. The expansion consists of placemats, showing the special properties of each faction.
Some Risk 2210 fans created extra factions. You can find these on risk2210.net .
Invasion of the Giant Amoebas
The fourth expansion consists of 30 Amoeba event cards, 3 extra Diplomat command cards and tokens to represent the Giant Amoebas.
This is a funny expansion that really twists the game around.