I'm using Now brand chlorella. The label says rich in chlorophyll, beta-carotene, RNA & DNA, broken cell wall algae. Other ingredients = none. It's a powder.
I have Solaray brand kelp with folic acid in capsule form, other ingredients are vegetable cellulose capsule and magnesium stearate.
They say kelp is one of the best natural sources of iodine; it is also rich in B-complex vitamins and vitamins D, E & K, also calcium and magnesium. It is often used as a salt substitute.