There is no reputable ETF that will give you 15% return. Even 10% real return is incredibly unlikely.
Be advised that they are not designed to be held over more than a day, although with the current bull market, they have not actually been hit by the decay factor inherent to all leveraged ETFs.
Other higher-risk ETFs would be things like solar/wind sector ETFs (e.g. TAN, FAN, PBW, IQCLN, QCLN, etc.) or bleeding-edge biotech (e.g. SBIO).
I'm sure there's SOME ETF that managed to do 15% returns over a 30 yr period, but that's just selection bias after the fact. It doesn't mean that ETF would do well this year, or next.