Cake decorating ideas with no colored frosting..only chocolate.?

You could smooth-frost it and do simple piping around the edges, or swirl-frost it and then use some edible flowers on top. ( A list of which flowers are edible should pop up quickly on a search engine.) Other edible things for the top or sides could be chopped nuts, candy, coconut, or cut strawberries. Get creative with the other things you have lying around. Keeping it simple and not going overboard ususally garners better results.