Why hasn't there been an abandoned carnival/fair as a ghost-type location? It'd be so aesthetic. Play some creepy carnival music, let the player go on rides/repair out of service ones, concession stands, carnival games, house of mirrors, merry-go-rounds, carousels,

Some wild Pokemon could be
>Mime Jr, Mr Mime (clowns)
>Swirlix, Slurpuff (cotton candy)
>Gastly, Haunter, Gengar
>Mimikyu (toy/prize)
>Shuppet, Banette (toy/prize)
>Misdreavus, Mismagius
>Smeargle (Caricature artist)
>Dirfloon, Drifblim (balloons)

An idea I had for a new ghost pokemon that could reside here is a unicorn ghost/steel pokemon from a carousel and it has the long metal rod going through its body.