I'm having trouble finding any well-developed open source Collectible Card Game projects.
I want to find projects to learn from and port to a mobile platform.
I'm one of the devs behind WTactics.org and would of course recommend our project over Forge as it's open, while the other is written to play Magic: The gathering against an A.I.
Art wise we have plenty and more to come since we hire artist(s). Code wise we have plenty of things cooking, like for example local client, a browser based version and card also online development tools.
Personally I wouldn't ever recommend anyone to play a CCG on a small mobile device, but I guess that's just my own preferences.
Anyways, a safe bet would be Wagic, if you, again, don't care much about it being a MtG centric AI. The good thing with it is that it even runs on a PSP, which I think is already more mobile than perhaps Forge is.
http://wtactics.org/ Has nice card art assets already
I've found nice one - Forge card game