ETFs w/ most active options trading:

$SPDR S&P 500 ETF (SPY.US)$ - 9.279M
$Invesco QQQ Trust (QQQ.US)$ - 2.943M
$iShares Russell 2000 ETF (IWM.US)$ - 918k
$Ishares Iboxx $ High Yield Corporate Bond Etf (HYG.US)$ - 494k
$ProShares UltraPro QQQ ETF (TQQQ.US)$ - 292k
$VanEck Gold Miners Equity ETF (GDX.US)$ - 230k
$ProShares Ultra VIX Short-Term Futures ETF (UVXY.US)$ - 230k
$Spdr Series Trust S&P Regional Bkg Etf (KRE.US)$ - 224k
$iShares 20+ Year Treasury Bond ETF (TLT.US)$ - 218k
$ProShares UltraPro Short QQQ ETF (SQQQ.US)$ - 204k
$iShares MSCI Brazil ETF (EWZ.US)$ - 179k
$iShares MSCI Emerging Markets ETF (EEM.US)$ - 145k
$Energy Select Sector SPDR Fund (XLE.US)$ - 136k
$iShares Silver Trust (SLV.US)$ - 126k
$Direxion Daily Semiconductor Bull 3x Shares ETF (SOXL.US)$ - 115k $United States Natural Gas (UNG.US)$
$SPDR Gold ETF (GLD.US)$ - 103k
$Financial Select Sector SPDR Fund (XLF.US)$ - 88k
$KraneShares CSI China Internet ETF (KWEB.US)$ - 81k
$iPath Series B S&P 500 VIX Short-Term Futures ETN (VXX.US)$ - 79k
-75k