NOT one of a kind, but difficult to find...
These were put out by Avalon Hill as part of their promotion to get 2210 tournaments going in game/hobby stores. If you were a game retailer, you could get these expansions for just the shipping cost. My local retailer ordered the amoeba one and gave me a copy after the tournament failed. I'm not sure if they plan on releasing any others, but you can check www.avalonhill.com and look under "tournaments" or something like that. If you have a local store and they don't hold tournaments, ask them if you pay them shipping if they will get a copy for you. They can even ask around and see if there are any Mars or other expansions laying around the AH warehouse or at distributors. The Mars one is the only one that I would be willing to pay some money for. Better yet, ask them to start a tournament .
Interesting side note, in the Amoeba expansion box there was a flier for Acquire tournaments. I never heard anything else about it, but they were running them under the Frontline name. I think that is the name for all AH tournaments now. It would be interesting if they started a Battle Cry tourney or something like that with expansions like new cards and such.