1. Alan Rickman alias Severus Snape.
Unforgotten. He was not only known for Harry Potter, but he was a very versatile actor who could not only perfectly mime the villain but also had very romantic roles. Among other things, he played a wonderful person who waited patiently for love alongside Kate Winslet and Emma Thompson. But, of course, he will be remembered by most of us as Severus Snape.
Unfortunately, he was not allowed to live very long but died of pancreatic cancer a few years ago. But through his many works, he will probably live forever. Fun fact, he hated all social media. When asked about it in an interview, he declined with thanks. Life without the internet was what he loved most. Good thing. That way, he could always be in the here and now.