RO red is the most consistent and available lump in my area that I know of. I believe they also make the GFS black bag lump, and as others have said, they make the BGE brand coal.
When I first bought my egg, I bought the BGE lump from the place I bought my egg, but noticed 2 issues...1, it was WAY too expensive, and 2, it had an odd smell, one that also gave everything I cooked a strong flavor, not bad nescessarily, but powerful. I believe it is the same lump as RO markets in the blue bags, normally for export to Canada I think. But I'm not 100% sure.
All in all, RO red is my go to most of the time. Many of the other brands I see on the Naked Wiz site and here are not available in my area