In 1975, producer Brian Eno and artist Peter Schmidt published a set of 100 cards each containing a single question or “brain bomb” to push them out of their mental rut.
Example: “What would your closest friend do? Instead of changing the thing, change the world around it. State the problem in words as simply as possible.”
You can buy their card deck (now in its 5th edition), come up with your own, or search for “oblique chirps” online.