Blue sea star by kactusficus. They really are this blue. This is not photoshopped.
Crinoid - starfish on coral by Okinawa Nature Photography, via Flickr
Marie Tartar. Sea squirt and amourous starfish embrace.
Starfish, Iconaster longimanus
sand dollars on the beach
Stimpson's Sun Star - Solaster stimpsoni - Washington State - feeds on sea squirts and sea cucumbers. Grows to 22"
Crown of Thorns Starfish, Acanthaster planci