godot/scene/theme/icons/toggle_off.svg

<svg xmlns="http://www.w3.org/2000/svg" width="32" height="16"><g fill-opacity=".5"><rect width="30" height="14" x="1" y="1" fill="#1a1a1a" rx="7"/><circle cx="8" cy="8" r="5" fill="#fff"/></g></svg>