I know Halloween parties are probably still off the table: indoor crowds of people eating, drinking, and exchanging other fluids in small houses and apartments.
But what about trick or treating? Assuming everyone wears a mask, which isn't even unusual for Halloween, it's primarily an outdoor activity and all the candy should be prepackaged until the kids get home. Sure, it'll involve small groups of kids and adults traveling together that aren't in the same household, but if you live in area where they've already reopened schools then that'll already be happening on a larger more regular scale. All of this is assuming you aren't in a high risk household.
A possible solution is instead of handing candy out at the door to set up a table at the end of your driveway or something and either hand out candy there or leave self serve bowls. That would also help stop kids from being packed like sardines on a small porch while waiting for someone to open the door.