What about getting him a book of short stories/anthology from the creator of Black Mirror, Charlie Brooker? The book is titled "Inside Black Mirror" and includes behind-the-scenes details about the show's episodes. You could also consider a Black Mirror-themed board game called "Nosedive" or getting him a t-shirt or hoodie with his favorite Black Mirror quote or imagery on it.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.