Any plant that creates shade helps.But, algae comes from sunlight. Some people color their water blue, which I have heard helps. Others, like me, let the bloom occur and deal with it. When temps drop the algae goes.

there is a rule of thumb about this-green cedar reeds growing in the water help clense the water

this link should help you figure it out. I think the “balance” of animal and plant life is most beneficial.
Plants suck up the excess nutrients that the algae are drawn to, so in a way just adding plants could help a lot.

Plants in the pond will generate algae that the fish will eat, and poop, fertilizing the plants that generate….very nice symbiotic relationship.

GGR