Iron Man (2008)

Iron Man (2008) launched the Marvel Cinematic Universe with $585 million globally, earning 20% more than the average 2008 superhero film. It outperforms #8 Guardians of the Galaxy by engineering the interconnected storytelling blueprint that generated $2.3 billion across subsequent sequels. With a 94% Rotten Tomatoes score and a $140 million budget, it achieved a 4.2x return on investment, the highest in this list's bottom five.