Then there's what I like to call Silhouette Romantic Suspense. By changing changing the color palette to moody blues instead of gauzy pastels, and switching up the setting to something more menacing -- an alley, a forest, a lair -- there's a new element of suspense and mystery.
Then there's ... what should we call this one? Silhouette Futurism? Amping up the color palate gives these more of a high energy, sci-fi feel.
Then we have what I'll call Silhouette Standoff. The figures are not running, but taking a stand against something or someone. Oppression? Dystopia? That white block text?
Classic Silhouette -- these are solid black and have a sweet old-fashioned feel. The problem with that is that they can make a book feel young. Can you tell the YA from the MG?