Value Investing outside of Stocks

I've been steadily investing 60/30/10 percent in VTSAX, VTIAX, and VBTLX. (S&P index, International stocks, and Bonds for the uninitiated.)

Looking at investing more, but given how expensive the market is, I'd like to look at other asset classes that are still accessible to the peasants like me. Can't do precious metals, as the sales tax in my state makes it a non-starter (they just changed the laws, used to be exempt...)

Any ideas would be appreciated. (Except collectibles. That screams "bad idea"...)