270towin Election Simulator Daily Analysis
FiveThirtyEight Election Forecast
270towin.com
This contains links to a number of analytical sites such as those from PredictIt, Politico, Charles Cook, and Larry Sabato
Real Clear Politics Presidential Approval
This contains links to most polls
Real Clear Politics: Biden v. Trump
This contains links to most polls
Real Clear Politics: Betting Odds
This contains links to a number of prediction sites
FiveThirtyEight
This contains links to most presidential polls and has good poll data for other races