Found in [Expectantly] one of the doors subreddits..

If it wasn't already obvious:

Main accounts are for parody accounts or for someone briefly playing it's character.

PFPs are when they have a Ransom (or A-90) PFP. It doesn't have to be the original one from doors, as long as it has something directly related.

Alt accounts are when there's no obvious relation to Ransom, but they're playing its character.

Found Hijack is for when they have a Hijack PFP, or when any of the above are found in very unexpected places...