Lot of stocks are admitted above the 50 day moving average. This is one indicator of potential overbought stocks.
From the chart below, you can see we are currently close (85%) to the highest values in the % of stocks that are over their 50 DMA. Its rare for stocks to move above 90% though a simplistic analysis of the below would say it haven't yet formed the top yet.
In any case, from Bespokeinvest.com, is a list of the most overbought stocks based on this similar measure: