I second whoever mentioned p2p lending on the first page as a possibility.
In 2014 I made about 12% on my p2p loan portfolio (pretty much tied the s&p 500). Once people realise that p2p lending is here to stay and will grow fast we could see a speculative bubble form in p2p lending stocks (with lendingclub being the best in my oponion). It could be similar to the 3d printing bubble, led by DDD. Now i am unsure if this will happen in 2015, but if it will happen, i imagine it will be within the next 3 years.
Of course a lot of crypto could go up massively, but I am not risking anything on alts until btc looks like it is about to turn, and even then ill just hold bitcoin.
Oil is a definite possibility, but as everyone else is saying, perhaps too many people are thinking the same way.
If the US stock market were to falter, USD would be one of the best investments you could make, but I am holding my index funds and will probably buy more. I imagine the US stock market will continue up, and would invest there as opposed to anywhere else. (I could be biased since I am in the US)
I do not believe in precious metals very much, look how long it took the gold/silver bubble in the early 1980s to deflate (look at a graph showing the price in inflation adjusted dollars). Personally I am tempted to open a small short position on gold.
Hmm... I'm sure there are other things i was looking at but they can't come to mind right now
