If the general market is in a bull market, I can only go long stocks or ETFs, since I feel that puts the odds in my favour. The only exception to that rule is that during a bull market, I can short sell inverse ETFs or the VIX index fund shown below:
Shorting VXX, shown above, is effectively like a bullish bet on the market, since the two are inversely co-related. I've been following this ETF for years now, and in my opinion, it tends to perform very weakly most of the time, consequently being a consistent money maker for me in the past.