Yes, You all may know it from final fantasy 8, The game I'm talking about is Triple triad extreme, it has many cards including customs, and plus It's not only final fantasy cards, There a few currency's
It is a small 24mb download and you don't register on the site..
You must wait a few hours before the password is emailed to you.
You will always find a game to play, it actually takes some effort...
I remember playing this game back about 4 years ago (although I'm not sure if it's exactly the same-- don't think it had "extreme" before). It was pretty sweet, and browser based.