Two to start with: comfort when your thoughts multiply, and an invitation to let God search them. Some of the best psalms for anxiety are this short.
In the multitude of my thoughts within me, your comforts delight my soul. Psalm 94:19
Search me, God, and know my heart. Try me, and know my thoughts. See if there is any wicked way in me, and lead me in the everlasting way. Psalm 139:23-24
Lord, my thoughts are crowding in again. You see every one of them, even the ones I’m embarrassed by. Search me and know what’s underneath. Let Your comfort reach the places worry has taken over. Lead me out of this spiral, one step at a time. In Jesus’ name, amen.