David Wasserman put together this very nice chart (below) of high quality, live interview average poll results by key demographic that provides a comparison between final pre-election polls in 2016 and this year. This is a useful comparison and makes for some interesting margin and shift comparisons between the two campaigns.
White college: 2016, D+12; 2020 D+18; shift D +6; comment: good!
White noncollege: 2016, D-29; 2020, D-18; shift D+11; comment: even better!
Age 18-34: 2016 D+19; 2020, D+29; shift D+10; comment excellent!
Age 65+: 2016 D-5; 2020 D+10; shift D+15; comment: great!
Black: 2016, D+78; 2020 D+75; shift D-3; comment: meh.
Hispanic: 2016, D+38; 2020 D+26; shift D-12; comment: sad!
It'll be interesting to see how these shifts stack up against good estimates of 2016 and 2020 actual election results by demographic (which, I should note, does not mean the exit polls).