Getting references after a company closes - what worked for you?

My manager was laid off too and I am unsure who to use as a reference. I have one former client who liked my work. 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.

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.