The G10 FR4 from ePlastics varies in color from batch to batch. The "natural" can be almost colorless, to a very slight green tint, to a very slight yellow tint. I've been buying the material from them for at least 10 years, and probably longer, but the color of the "natural" has never been an issue. If you stack a few sheets together and hold them up to a light they will show the color fairly well. However, if you hold a single sheet up to a light, the color will hardly be noticeable. It's never been a problem... Yeah, "natural" and "black" are pretty much standard from ePlastics. There are some manufacturers who make other colors but there is no true "transparent". This stuff is heat and pressure-built glass/resin. The glass fibers give it some color, but the resin is usually the colorant. When you work with the material you will see the glass fibers. As an aside, if you are allergic to fiberglass, you probably want to avoid G10 FR4. Don't breathe the dust, and wear something you don't mind getting really dirty. The dust produced when sanding this stuff will cause itching, and I'm sure it's not great for your lungs. I'd just suggest that you use common sense when working with it.
Also, when machining the material, you might want to use medium to slow speeds on sanders or Dremel tools. That way you don't throw the dust all over the place. And, don't sand or machine it inside your house. Take it outside your living area. (Either machine it in the garage, or you'll find yourself sleeping in the garage!)
Now I have go figure out what happened when I sawed the lip slots in my last 6 baits. Four of them run great and the other two look like they're in some type of death spiral!!! All six were cut at the same time (stacked bodies) and after looking REALLY closely, two of the slots are skewed... I've only been building baits for 40 years, and I still manage to screw them up. Lee Sisson I am not!