David: 73 psalms
(The Septuagint and Latin Vulgate credit a few more to him.2)
Half of Psalms was written by King David at various points in his life—and not all of them were good times. David’s psalms show how a man of God prays during times of hardship, loss, joy, and guilt.
Asaph (the family): 12 psalms
The sons of Korah: 11 psalms
Back in the book of Numbers, a man named Korah rebelled against Moses and Aaron—and God caused the earth to swallow him up. His sons survived, though (Nu 26:11), and continued to serve in the house of the Lord. They share one psalm (Ps 88) with the wise man Heman.
Solomon: two psalms
Moses: one psalm.
Ethan the Ezrahite: one psalm
We don’t know much about Ethan, except that he was very wise, and Solomon was wiser (1 Ki 4:31). Sorry, Ethan.
The remaining 50 psalms aren’t credited to any one author.