Using more colors than the standard purple hue for the Forms app’s form tiles helps the app user quickly choose the correct form in the Dashboard. These colors are defined in the Form element in the Designer. Select the form element (at the top, with the form name), go to Element Properties and select the Styling tab. Select a new Background color for the tile. The tile’s label text is black, but you may change this in the field Label color. Note that these tiles only appear in the Forms and Web Apps, so you must open one of these to see the changes you have made.