When I read in the Bible things like
For I know that the LORD is great, and that our Lord is above all gods. { psalms 135}

Does this mean other Gods do exist and that God is more powerful than them? Or as I thought no other Gods exist.

This is not the only line in the bible which hints that other Gods do exist.
So are there other Gods or is he the only God?
Thought I had this crack now I'm confused again.

Thanks.