Does Texas require some know the specific type of drug they are possessing, or merely that they are possessing a controlled substance of some kind?

Federally, the answer is no. A defendant charged with importing or possessing a drug is not required to know the type and amount of drug. “[A] defendant can be convicted under § 841 and § 960 if he believes he has some controlled substance in his possession.” United States v. Ramirez–Ramirez, 875 F.2d 772, 774 (9th Cir.1989).

Some States disagree with this and require knowledge of the specific drug charged. The language of 481.115 seems vague as does case law such as this:

To prove unlawful possession of a controlled substance, “the State must prove that (1) the accused exercised control, management, or care over the substance; and (2) the accused knew the matter possessed was contraband.” Evans v. State, 202 S.W.3d 158, 161 (Tex.Crim.App.2006);

Any help would be greatly appreciated!

I think you cite the only language the Texas courts have used in describing the elements of the offense. I believe that, unless a mistake of fact defense is raised as to the precise nature (chemical makeup) of the substance, you have proved all that is needed to convict once you prove possession of a substance that proves to be a controlled substance.

Because the law only states that the person must know the matter possessed "was contraband," I believe that he is required to know it was an illegal substance but not specifically what illegal substance it was. I had once case along these lines, Quinn v. State, 2013 WL 2152641, where the court didn't address the question directly but just said that the evidence was sufficient because he knew the bag contained "illegal drugs" or "contraband."

I am guessing Texas law will conform to (require no more knowledge or intent than) federal law, which will soon be decided in McFadden v. U.S., No. 14-378.