Oh, that's easy.
Botryocladia is the obvious one that comes to mind.
Very attractive, not hard to find, and prefers lower light.
I keep having to find unique low light areas in my tank for it, cause it keeps getting pale in the usual light in my tank, which is T5HO.
Most of the Red Macros prefer lower light.
Live-plants.com has a great Red Sampler pack that lets you get more than one kind of Red Macro and is a great deal. Pretty sure they also have Botryocladia right now as well.
