The dusky nembrotha, Nembrotha kubaryana, is one of the wildest colored nudibranchs I have seen. Bright orange rhinophores and mouth with vibrant neon green stripes down its black body.
Chromodoris tinctoria
Bornella anguilla, or "eel nudibranch.' This has been seen only once in Hawaiian waters. I had to travel to tiny Gato Island near Malapascua, Philippines to finally find it. It is named the eel nudibranch because of the way it swims, undulating sideways through the water.