Who do I ask for a reference after a layoff? - what worked for you?

The company closed and I am not sure how to reach former colleagues. I am in Albuquerque, in case local advice matters. I have one former client who liked my work. How do you ask politely?

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

I kept a note of my results so my references could be specific. They appreciated it.