do you have a favorite author you have collected every book they wrote??

Yes. Robert Heinlein..😷

I had a period that I collected and read books by Len Deigton.
Same for Philip Kerr

O. Henry

Douglas Adams and Richard Osmond.
I have all Bob Mortimers books, but that's only four, and one of them is an autobiography.
I used to have quite a few James Herbert and Stephen King books, but they seem to have gone astray.

I did own everything Stephen King book before my ex-wife sold them at a fucking garage sale. They were all hard copies too. That was many years ago though and I have forgiven her.

Robertson Davis and Tea Obreht. And short stories by Kelly Link.