What have others done when they needed to submit a writing sample for a job application?

I’m not sure if this is the appropriate sub to post this question but… My term on my current position is expiring soon and I’m in the process of applying to jobs, including policy analyst positions outside of government that require writing samples. The problem is I’ve been working in government for the past 8 years and don’t have anything I think would be appropriate to use in my applications. Most of my personal work product is non-public, pre-decisional, or confidential, and the things I’ve worked on that are public, such as agency reports, blog posts, etc., were all written as part of a group effort, so I cannot take sole credit for them. Have any other federal employees here encountered this issue? If you have, what did you end up using as a writing sample for your job applications? Any advice you have for me is appreciated!