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. It has been weighing on me all week. A colleague offered to vouch for me. How do you ask politely?

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

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