I have found all the games on the Steam Summer Sale 2020 with a minimum of -80% and 90+ positive ratings. The best deals of Steam Summer Sale 2020.
If you are looking for some dead cheap games at Steam, you will find the most discounted games in this list. The list contains 60 games for you to add to your Steam library.
Source: N4G PC All the Best Deals on Steam Summer Sale. -80% with 90+ ratings.