If you delete a user, there is an alert to say which lead type has an action that references this user. But it would be helpful to see which lead group this is in (especially when you have LOTS OF LEAD TYPES with the same name!)

We also need to know which workflow this user is part of. which links to this suggestion here too:

https://flg.canny.io/flg/p/search-for-leads-still-running-a-specific-workflow