We often get to see awesome illustrations and 3D renders from many great artists. I find particularly cool realistic works, that if you see from a certain distance, you can't tell it's not real.
If there is something that can bring value for a project even before it's done I can say that are the renders. It's a way to show to the client how it will be the
Being a great fan of comic books, I always loved the visual identities used for some famous characters. Most super-heroes logos are like a incorporation of many aspects of the characters and their superpowers. I always liked Hulk logo as everytime I look at it I always remember his famous quote "Hulk Smash".