Here's a possible implementation of the 2021 NFL Draft in the event that the 2020 season needs to be cancelled.
The draft will be held with the same order as 2020 (Bengals #1, Redskins #2, Lions #3, and so on), and will proceed until 256 players have been selected. Every team starts with a budget of $1000, which may be allocated towards as many or as few prospects as the team chooses, however, at no point during the draft may the number of players remaining to be selected exceed the total amount of dollars remaining among all 32 teams. Therefore, the maximum bid for a player is the number of total dollars still in play minus the number of players remaining to be selected (and if this much money was spent on a player, all remaining players would sell for $1). The Bengals will nominate the first player, followed by the Redskins, and then the Lions, and so on, but a team's nomination is skipped if they have no money remaining (that is, after the Bengals nominate a player, if the Redskins are out of money, the Lions nominate the next player).
When a player is nominated, every team has the same amount of time as in a normal draft (10 minutes for the first 32 picks, etc.) to decide how much money, if any, they want to blindly bid on that player. The player is awarded to the team that bid the most money on him. If two teams, say the Bengals and Redskins, bid the same amount on a player, that player would belong to the team picking earliest, in this case the Bengals. If no team bids money on a player, the player is awarded to the nominating team for a price of $1. Only the winner's bid amount is revealed (e.g. "Trevor Lawrence has been awarded to the Jaguars for $400"), so as not to reveal a team's intent to target a certain position later in the draft.
Any trades that would have involved picks in the 2021 draft will be applied instead to the 2022 draft, any trades in the 2022 draft will be applied to 2023, and so on. Any compensatory picks that would have been awarded in the 2021 draft are instead awarded in the 2022 draft (and none would have been awarded to the 2022 draft anyway, since no season was played, and hence no players changed teams via free agency). Instead of the Patriots forfeiting their 2021 3rd round pick, they will forfeit their 2022 3rd round pick instead.