Depending on the markets quite a few stocks trend with SPY... Back when the market plummeted in the Spring a large majority of the stocks trended in lock step with SPY to the point where I thought my all of my systems were lying to me... $DJI, SPY, AMD, AAPL, MSFT, MU, and a bunch more had virtually identical charts for days...
All that being said, I'm not sure how you would devise a scan to find stocks trending with SPY...