I love the super hero concept because there is so much you can do with it. You have a great color palette of primary colors to work with as well as a mix of common patterns (e.g., stripes, stars, polka dots, etc.).
Invitations, Banner, Cupcake Toppers, Gift Tags, Candy Bar Wrappers, Place Cards and Water Bottle Wraps via Printabelle
This is a great theme for boys (or girls) that can easily be implemented due to its common color palette. Plus, there are so many super hero-specific paper goods, toys and free printables out there. You just have to do some digging. For additional ideas, visit my super hero birthday party Pinterest board.
For other awesome invitations and party goods, check out Tiny Prints.