Andres
G.O.A.T.
His career grass record is 26-18, with no titles and one final (Halle 2005). Without his last flukey Wimbledon SF, his record would be 21-17. Far from stellar.One of the most all-around players is Marat Safin. He can hit winner off both sides, his serve is deadly, excellent hands at net, such skill.
He's also proved to be an adept grass-court player in addition to hard courts, and he's not half bad at clay.
In fact, he's sort of mediocre on grass. To my eyes, he's much better on clay than on grass.