
The best example of a (short term) overbought breadth indicator is the S&P Bullish Percent. Look for a push to 1,315-1,335 in the S&P:

This clock reached its time on October 19th 2017. This was a forecast for a "Major Market Top". Unfortunately, I can't find the link for the source material (but years ending in "7" was one of the red flags) but I thought it interesting enough to start this countdown clock 2 years ago.
I did a post on this here
Let's see if it carries any credence.