America Votes 34, by Rhodes Cook, has just been published. It has election returns for 2019 and 2020, for president, U.S. Senate, and governor, by county. It also has returns for U.S. House elections. It is part of the series that has been published, every two years, starting in 1956.
Most large and medium-size libraries have collections of America Votes.
The Federal Election Commission still hasn’t published its 2020 book of election returns, which will be called “Federal Elections 2020”. The FEC book is free but has no returns for governor, and no county-by-county returns. Both America Votes and Federal Elections 2020 have primary returns as well as general election returns.