Art Deco is a style that became increasingly popular during the 1930's and 1940's. "It is aneclectic style that combines traditional craft motifs with Machine Age imagery and materials". In true Art Deco style, you'll see lots of bold colors and geometric shapes. It is truly one of my favorite styles, and I'm excited to see it become popular once again. Why don't you try making a Great Gatsby inspired invitation for your next party? Creative Market has an amazing selection of resources.
Wing's Art Studio has an amazing collection of backgrounds, frames, seamless patterns, and more.
Fizzy Images has some fun seamless backgrounds that are perfect for creating Great Gatsby themed invitations.
Art Deco Vector Elements are ideal for creating a 1920's theme invitation.