Here are 2 Amy Rose Classic themed phone cases.
Each is available in the Sega Shop. But look at the holes for the camera...they're in vastly different places/sizes, and the blue one has some kind of button space edge? They both say they're for the iphone only, but which one? You'd have to be careful in selecting it for your phone since they're so different...and 28 dollars EACH when you find it. For a piece of plastic in a shape, 28 dollars seems expensive.
The first case is all matte pink, but has a 'polka dot' almost pattern of Amy faces. Some are a shiny sihloutte, with others have her line art details. The right side case is powder blue, with "AMY" spelled out in abstract/geometric font, with her head imposed over the 'a', to create a sort of design. They're both great for Amy Rose fans, though their price is a bit steep in 2018 / 2019.