Here's a great series of fan-made poster art for several films in the Marvel and DC cinematic universes. The posters are by Mat Guillen Designs, and they feature Spider-Man, Batman, Hulk, Captain America, Thor, and Iron Man. As you can see, the artist has a very energetic style that makes you feel the awesomeness of these characters.
Mat Guillen is an experienced designer with an adaptive visual style, He has worked with a comprehensive array of studios including Disney, Paramount, Universal, DreamWorks, Warner Bros., Legendary, Film District, Lionsgate and Summit. From blockbuster sci-fi to all-ages animation, his area of expertise has no boundaries.