Who do I ask for a reference after a layoff? after 8 years as a nurse's aide

The company closed and I am not sure how to reach former colleagues. I have been trying to stay organised about it. A colleague offered to vouch for me. Is a client acceptable?

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.