We're still in a low IV environment across the market, but there are some good opportunities to be found.
$USO - very high IV (90th percentile) so this is a name you want to be trading around. It is the only decent stock in the market with IVP > 50. I'd suggest an Iron Butterfly centered around the 14 strike for Aug 31. Even with a large move in the stock, the consequential drop in IV should make up for it. I'd consider this a low risk opp. to play short oil IV.
$XLF - the bank stocks have been range bound as nobody can quite guess where rates are headed (long term nowhere but up). I'd bet on a continuance of this sideways, range-bound price action by selling an Iron Butterfly 27.5 for Aug 31 expiration. The breakevens on the position are at the edges of the range so if you see a breakout, I would exit.
$GLD - gold has been in a big down trend recently and could be ready for a bounce, albeit not a strong one. The bull case for gold isn't strong right now. When $GLD trades up, though, IV tends to follow, so I propose the Aug31/Oct calendar centered on the 119 strike. If $GLD breaks below it's recent lows and keeps going, you don't stand to lose much from this trade at all. Risk/reward favors a tepid bullish stance accounting for a rise in IV.