Nine Lives: I loved this. Ann Cleeves Swanson Peter (2023)

Nine strangers each receive an unremarkable envelope with no return address. Inside is a single folded sheet of white paper bearing a list on which each recipient recognises only one name: their own. If you are on the list, you are marked for death, and one by one the recipients begin to meet their end. The letter may be the most life-changing they have ever received, and it may also be their last.