I was already pretty intrigued by the polling situation in Arizona. There have been quite a few good numbers for Biden this month, and there are reasonable ways of calculating a polling average that now puts AZ left of the tipping point https://twitter.com/JimSmall/status/1302013747330834432?s=20

In the last month, we've got Biden+10 in MC, Biden+8 in Fox, Biden+7 in Emerson (which has a GOP house effect at the moment). The last real "good" news for Trump, as far as I can tell, are the Biden+4/5 polls from late July in CNN and Marist

Also Change Research was just Biden+2, though at N=344 I'm not sure it's getting a ton of weight exactly.