In a year devastated by a global pandemic, every death felt a little heavier. And while we may not have personally known the many stars we lost, we did know them — for the words they wrote, the songs they sang, the characters they inhabited. Entertaining us, challenging us, and moving us with their art, their talents, and their stories, all of these luminaries left an indelible mark on pop culture. Here, their costars, collaborators, and celebrity fans pay tribute.