Try using one of the templates for Google slides from the site of Ryan O'Donnell.
There are so many different templates to choose. You can use social media posts, like Instagram, Facebook, and Twitter. Maybe having students create a Magazines like Time or National Geographic. These are not just covers, they are full articles or a series of articles that could be assigned to a team. How about a Time Magazine issue from the Gettysburg Address?

Then using the template Ryan provides, you can create awesome comic covers or whole comic books. Think of the possibilities! Ryan also has a link for a superhero creator website so students can create their own superhero. Again think of the possibilities!