Sweatshirts design

I am looking for creative designs for sweatshirts that will appeal to ages from 14-30. The style of design I am looking for is something romantic and I want the sweatshirts to match each other as they are intended for couples they matched and complemented each other. I have a rough idea for the concepts, but I'm open to any ideas the designer may have. I'll need different designs for all ages so the designs should be attractive to teens and adults. I'm looking for unique and eye-catching designs that will stand out.