Who do I ask for a reference after a layoff? - 8 months and counting

I worry a reference will only confirm dates of employment. This is my first time dealing with any of this. A colleague offered to vouch for me. How do you ask politely?

A client reference worked well for me. It shows you deliver outside the company too.

Ask former colleagues and supervisors in a short message and give them a summary of the job you are applying for.