PlaceIt
They don’t just have the largest library, they also have the easiest way to make mockups. Just drop your design and in & they generate the mockup! In addition to a huge archive of mockups they also have animated YouTube end screens, YouTube channel art, Instagram and YouTube story templates…the list just goes on and on. You really need to just check out PlaceIt for yourself so you can see all of the incredible templates they have. Check out PlaceIt here.