Have you read any of the Adam Nevill books?
I didn't like Apartment 16 but The Ritual and Last Days were both very good.
The Ritual is about a group of hikers who get lost in a remote Swedish forest and realise they are being hunted and picked off by something not quite human.
Last Days is about a documentary film crew hired to investigate a suicide cult and the houses and compounds they lived in. The few surviving ex-cult members have started to die in mysterious circumstances, after claiming they have had a visit from some old friends. Friends who died a long time before.
Otherwise, anything by FG Cottam is fantastic. I love him.
I think my favourite is The Waiting Room, which is about a disused railway station, now on private land, which seems to be haunted by an evil spirit.
But his latest one, Colony, is also very good. It's about a colony in Scotland who one day just vanish from the island they had made their home on. Years later a rich newspaper owner sends a team of experts in varying subjects to investigate the island, and the disappearances and spooky events start all over again.
Lost Souls, about a boat that belonged to a devil worshipper, whose subsequent owners all seem to die violently, is also very good.
And Broadmaw Bay is a bit Wicker Man like in its plot, a family from London move to a village in Cornwall where the locals practice an odd custom.