A conversation in another thread made me think about that I really like a lot of object-based ghost Pokemon and would really like to see more.
One thing I'd really like to see would be the
https://en.wikipedia.org/wiki/Kasa-obake a Japanese umbrella spirit. They seem to be mischievous and like to play pranks, so I could see them being Ghost/Fairy, or maybe Ghost/Water (umbrella?) or Ghost/Flying (ever lost hold of an umbrella during a storm, hurricane?)
I'd also kinda like a Pokemon based on a treasure chest that could maybe throw fake gold and/or jewels at the opponent. In it's Pokedex entry it could be said to play tricks on greedy humans by leaving trails of gold coins/jewels lying around that later turn out to be completely worthless, or even just glamoured grass/dirt/pebbles.
That of course also kinda sounds Ghost/Fairy like... particularly in that it would be a natural candidate for Dazzling Gleam. But I could also see Ghost/Psychic (it manipulates others into thinking pebbles and dirt are jewels/gold via telepathic suggestion) or maybe Ghost/Steel.
Maybe it could be an evolution line...an old fashioned...uh you know those leather pouches they used to store their money in during Medieval Times? That later evolves into a Treasure Chest.
A chipped porcelain ballerina figurine would also be something I'd like to see. Possibly pure Ghost. It could be a melancholic, but helpful creature that helps people to let go of sad past memories (blergh...that sounds part Fairy yet again...
)
And finally some sort of hat/helmet/crown (maybe multiple variations) that likes to put itself onto the heads of people and causes them to take on a personality that is fitting for the hat. Could be like Orciorio, with maybe 4 variations that each have a different sub-type: A knight helmet (Ghost/Steel) a top hat (Ghost/Psychic, due to stage magicians) a flowery bonnet or straw hat (Ghost/Grass) and a woolly winter hat ( Ghost/Ice)