This year is weird, you guys. I have far fewer gifts to give this year than I normally do, thanks to doing Secret Santa with my family, an agreement of no gifts (except for the kids) with my in-laws, and Secret Santa with friends as well. So I have a little leftover gift-thinking energy to share with you.
But only a little, so I only have one idea for you: give the gift of books.
If you know someone who has five billion books and you have no idea what they do or don't have, give them a gift card to a bookstore (may I recommend Cassy's employer and my personal favorite bookstore, Barnes & Noble). They have lots of cute gift cards highlighting different series and characters and genres so it still feels a little customized. There's also the "book accessory" category, with so many types of bookmarks, book lights, journals where you keep track of the books you've read and enjoyed or hated, book-of-the-month clubs (are those a thing? if not, I think I found my million-dollar idea), etc.
If you have a kid on your Christmas list, give them books. Any books (as long as they're approximately age-appropriate. I wouldn't recommend Stephen King's Carrie for a three-year-old). Little kids haven't learned yet whether they do or don't like to read. Baby books are super-fun to shop for: bath books, picture books (both classic and contemporary), finger puppet books, touch-and-feel books... so much fun. And it gives you an excuse to play with them yourself. "Oh, I'm just shopping for my kids..."
For the older kids and teens who like books, that's easy. Get them a book they've asked for or a gift card.
For the ones who think they don't like books, prove them wrong. I have a nephew who likes to play Minecraft. There are tons of guides on Minecraft that, while they aren't narrative or particularly educational, they're books, and they're related directly to something he's interested in. Look at lists of books for "reluctant readers" and see if you can find something that might catch the eye of the kid or teen on your list.
For adults, look at coffee table books. My grandfather likes antique cars and hand-lettered signs. My step-mom crochets. My uncle is an Elvis tribute artist. All of these topics (and so, so many more) have at least dozens of coffee table books about them. Alternately, I could find a history of hand-lettered signs, a book of crochet patterns, and an Elvis biography, if they're more inclined to reading.
"Books" doesn't have to be literal, either. For a higher-price gift, look at e-readers or tablets. I'm fairly certain you can gift e-books themselves. Maybe a magazine would be a more appropriate gift for your recipient.
There are also those little humor books that make fun little stocking stuffers and often wind up in a basket of bathroom reading materials. There are cookbooks, novels, travel books... that's the amazing thing about books. There are so many of them, and they're so diverse, there is literally a book for everyone... even the people who think they don't like books.