Who do I ask for a reference after a layoff? (update)

My manager was laid off too and I am unsure who to use as a reference. I am in Kansas City, in case local advice matters. HR only confirms titles and dates. Is a client acceptable?

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

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