Alison Krauss
As of 2018, she has won 27 Grammy Awards from 42 nominations, tying her for the second most awarded recipient alongside Quincy Jones, second only to classical conductor Georg Solti, who holds the record for most wins with 31. She is the most awarded singer and the most awarded female artist in Grammy history.
Grammy Award for Best Song Written for Visual Media
Alan Menken has the most wins (5 times). After him, only James Horner, Howard Ashman and T Bone Burnett have multiple wins (2 each).
Diane Warren has the most nomination with 10, followed by Alan Menken with 9, Babyface with 7, James Horner and T Bone Burnett with 4 each, Madonna, Howard Ashman, Tim Rice and Michael Kamen with 3 each (all of them won at least one Grammy).
Sting is the most nominated artist without wins (nominated 3 times). Stephen Sondheim, Elton John, Elvis Costello and U2 were nominated 2 times without winning. 
Babyface was the artist with more nominations in a single year with 3 nominations in 1997 but failed to win the award that year.