Pillow inserts don’t need to look fancy, they just need to be long-lasting. You don’t want something too flimsy or something that’ll sag easily, so most people choose polyester and down alternative throw pillows because they’re moldable, durable, and inexpensive. You can find plenty of throw pillow inserts on Amazon—the top-selling inserts at the time of publishing are the EDOW Throw Pillow Inserts (set of 2).