My goto was basically: "I want to do <x>. What do you think?" (but a bit more diplomatically phrased)

Some examples:

- Change the way standups are done - Do something not directly related to the team - Do debt - Change / take over the way a project is being done

In general it worked well because either I had a good idea in which case I'd often get the agency to do it, or perhaps not directly but a path towards it or it wasn't and I learnt something.