Well I was recently tempted to play Lord of the Rings Online, which was originally a subscription game but went free-to-play recently. As far as free games go they honestly don't come more professional than that.
If you don't mind putting down the token payment for the actual game itself (and it really is absurdly cheap these days) Guild Wars remains subscription-free and still one of the best MMOs ever made.
Oh, and the expression is "in vain". If you were searching in vein, you'd be elbow-deep in blood.