Besides Isaiah?
Seriously? No book, no author of the Bible agrees with your assertion. Especially Isaiah.
"You alone, Lord, are God." Isaiah 37:20
"Before Me there was no God formed, And there will be none after Me." Isaiah 43:10
"'I am the first and I am the last, And there is no God besides Me." Isaiah 44:6
"Is there any God besides Me, Or is there any other Rock? I know of none." Isaiah 44:8
"I am Yahweh, and there is no other; Besides Me there is no God." Isaiah 45:5
"Surely, God is with you, and there is none else, No other God." Isaiah 45:14
"I am Yahweh, and there is none else." Isaiah 45:18
"Is it not I, Yahweh? And there is no other God besides Me, A righteous God and a Savior; There is none except Me." Isaiah 45:21
"I am God, and there is no other; I am God, and there is no one like Me" Isaiah 46:9