Are you kidding me? That's an awesome potential giveaway!
I'm an early adopter, but this account is used in an experiment I go through (grinding my way up without external investments, transfers or delegations from myself - only organic growth of the account). So let's say one of the early ones - Selenia Sky, which had its time of glory before many other options appeared. A 3 mana +1 ranged attack dragon card. I still love it and use it often.
Good luck!