ETFs w/ most active options trading:

$SPDR S&P 500 ETF(SPY.US)$ - 8.128M
$Invesco QQQ Trust(QQQ.US)$ - 2.948M
$iShares Russell 2000 ETF(IWM.US)$ - 1.095M
$Spdr Series Trust S&P Regional Bkg Etf(KRE.US)$ - 322k
$Ishares Iboxx $ High Yield Corporate Bond Etf(HYG.US)$ - 312k
$iShares MSCI EAFE ETF(EFA.US)$ - 249k
$iShares 20+ Year Treasury Bond ETF(TLT.US)$ - 221k
$iShares MSCI Emerging Markets ETF(EEM.US)$ - 214k
$ProShares UltraPro QQQ ETF(TQQQ.US)$ - 210k
$ProShares UltraPro Short QQQ ETF(SQQQ.US)$ - 188k
$iShares Silver Trust(SLV.US)$ - 148k
$iShares MSCI Brazil ETF(EWZ.US)$ - 145k
$iShares China Large-Cap ETF(FXI.US)$ - 143k
$ProShares Ultra VIX Short-Term Futures ETF(UVXY.US)$ - 136k
$Energy Select Sector SPDR Fund(XLE.US)$ - 135k
$Financial Select Sector SPDR Fund(XLF.US)$ - 128k
$VanEck Gold Miners Equity ETF(GDX.US)$ - 107k
$SPDR Gold ETF(GLD.US)$ - 104k
$Direxion Daily Semiconductor Bull 3x Shares ETF(SOXL.US)$ - 101k