Another possible short idea is the British pound. It's already been clobbered since the Brexit vote, but could there be even more downside to come?
The key level to watch is 120, which also corresponds to the 2000/2001 lows. It's already tested this level twice, in October and January, but looks like it may test again.
If it fails to hold key support at 120, that would be the signal to short.