Monolith Arts is running a Kickstarter called
Lost Souls, for a line of 3d printing STLs for ghosts of various kinds. There's some cool Lord of the Rings inspired figures as well as some others that lean more towards standard fantasy archetypes. Some of them could certainly be useful as Nighthaunt heroes or to add some variety to units. The Kickstarter is in the last 72 hours, and the core pledge currently contains 70 miniatures.
There's also a free sample download available.
Edit: The campaign is now in its last 48 hours, and close to unlocking all the stretch goals: