You could run a census for that type of stuff. If you're not up for it, just go the the most trending pages of what's in the market. Check demographics, do a little digging on what's popular that might just remain popular for a while, I'm sure you'll have enough open-access data to build a reasonable conclusion. If I had to say, streaming and gaming accessories, peripherals, or devices, on the top of my head.
You're going to need more resources if you intend to stay ahead of the trend but it's got it's own risks.