Both algae and most water plants love the sun. The water lily for example requires at least six hours of direct sun-light to bloom. If you plant fast growing floaters in your pond when you put your first lilies in then they will quickly cover the surface area required. As your lilies get bigger, you can remove your floaters. Almost everyone thinks of water lilies first when they think of ponds.
Some tropical varieties bloom at night.
Some, too, are fragrant. Two ideas to keep in mind when considering the wide range of these plants available is that they really like still water and that Hardy ones need 50 degree Fahrenheit water for sustained new growth while Tropicals need about 70 degree water. Deep water aquatics are good plants for areas of the pond that have movement of water or partial shade. Like lilies they like up to 15 inches of water over them. Floaters are plants that are not rooted in soil and float on the surface.