From its name ones can guess that Commodity ETFs invest in commodities, such as precious metals and futures. The gold exchange-traded funds were among the first commodity ETFs and they have been offered in a number of countries. Generally, Commodity ETFs are considered as index funds, however these funds track non-securities (non-stock) indexes (commodities indexes). Commodity ETFs provide opportunity to invest into commodities market and therefore they may be subject to regulation by the Commodity Futures Trading Commission.
Naked options trading is very risky - many people lose money trading them. It is recommended contacting your broker or investment professional to find out about trading risk and margin requirements before getting involved into trading uncovered options.