There are a number of different Ghost Types in Phasmophobia. Please keep in mind that while each type of ghost has a general behaviour, they do not always conform and can behave very out of character. Also keep in mind that all ghosts except in the tutorial will eventually become hostile and try to kill you. We have created a Phasmophobia Ghost Identifier to help make ghost identification easier.
Strengths: They become more active when people are around, potentially making them easier to find and identify. They can move objects at great speed.
Weakness: Becoming more active makes them easier to find and identify.
In-Game Experience: I've not really noticed objects moving slower or faster, though it is often true that an Oni will move stuff around a lot if there is stuff for them to move.
Strengths: They often drain your sanity faster than other ghosts. This can make them become very active and hunt more quickly.
Weakness: Smudging the Yurei's room will cause it to stop wandering.
In-Game Experience: I haven't really noticed anything out of the ordinary with this one, although a good Smudge may calm them for a time.
Strength: Demons will attack more often than other types of ghosts.
Weakness: Asking successful questions on the Ouija Board won't drain the user's sanity.
In-Game Experience: Yes, they can attack more often. However, I've seen other ghosts do the same thing. As for the whole Ouija thing, it's not 100%, though this may be a bug, because I have seen them tank a person's sanity with a successful question.
Strength: They are shy, which can make them harder to find.
Weakness: The ghost will not hunt if there are multiple people nearby.
In-Game Experience: Yes, they can be very quiet and therfore hard to find. Keep in mind the trick about hunting: Just because you are all walking close together doesn't mean anything. It won't hunt if there are multiple people nearby, which means close to it. So if there are a few people close to it, you should be able to keep it from hunting. Forming a cuddle puddle away from the ghost won't have any effect on this, since as far as the ghost is concerned, you aren't nearby.
Strength: They move significantly faster when hunting.
Weakness: Hiding from the Revenant during a hunt will cause it to move very slowly.
In-Game Experience: I think of this ghost as one of the most dangerous. It will run you down if you try to run from it, though you can buy yourself time by hooking it on corners, stairs and furniture. But you better hide fast! If you move quite slow this one is a speedy killing machine.
Strength: Increased chance of an attack in the dark.
Weakness: Lowered chance of an attack with the lights on.
In-Game Experience: It is true that if you keep the lights on it often will attack less. But that doesn't prevent an attack. Having the lights off, however, does cause it to attack more often. In part because of its nature and in part because your sanity drops much faster in the dark. Keeping the lights on can help, but it is not a sure bet.
Strength: A Jinn will travel faster if its victim is far away.
Weakness: Turning off the breaker will prevent it from using its special power. Guessing that is its faster movement.
In-Game Experience: They often play with electronics and lights, though many other ghosts do this as well. Turning off the breaker will tank your sanity quickly and that just means more hunts will happen faster. It is also true that they are territorial, so if you mess with their room too much they will become hostile much more quickly.
Strength: The Banshee will target only one person at a time.
Weakness: Banshees fear the Crucifix and may be less agressive near one.
In-Game Experience: These ghosts are dangerous. You can stop them from hunting permanently if you figure out who on your team is targeted. Once you know who the Banshee is after, have them stay in the truck. Then the rest of the team can investigate and it won't hunt, because they aren't its target. I don't know who started the silly rumor that it always targets the host, but that is incorrect. The Banshee can target anyone and will remain fixated on that person until it kills them.
Strength: Looking at a Phantom will quickly take down your sanity.
Weakness: Taking a photo of a Phantom will make it disappear.
In-Game Experience: They do hit the sanity hard when you look at them. If you take a photo of them they will instantly vanish and in the journal your photo of a ghost will appear empty, but still be counted as a photo of the ghost. That is a great way to identify the photo. Keep in mind, however, that for some reason if you look at another person's photo in the journal it is almost always empty. So it has to be the person that took the photo that sees an empty photo, to be sure it's a Phantom.
Strength: A Wraith almost never touches the ground so it can't be tracked by footprints.
Weakness: Wraiths have a toxic reaction to Salt.
In-Game Experience: Well, this is one ghost many people misunderstand. It can step in Salt, usually only once, but it does happen. After all, "almost never" is not "never ever." As for the toxic reaction, maybe it is more likely to show itself after stepping in Salt. It's hard to say since, well... I've not really noticed it does much. However, if a Wraith steps in Salt and you immediately use a UV Light, you won't see green footprints. That is a good indication it is a Wraith.