Age of Empires: Expandable Card Game is a physical card game adaptation by Journeyman Press, based on the classic computer game of the same name. The initial release, called Base Set, was published in 2000, and then it was followed by the first and last expansion pack, called Nautical Set, published in 2001. Shortly after this release, Journeyman Press unfortunately went bankrupt and thus no further contents have been published. You can find all the officially printed cards in this page.
Frankly, I've never been a card game geek, but I love Age of Empires. I'm thankful to AoE: ECG to help me realize how admirable culture the card/board games really are. I really would like to collect some other collectible card games too, but I don't think I would start sometime soon. It took around 3 years of non-stop searches, trades and purchases to complete this damn set of 536 unique cards :)