Down Bound Train (Popular Library 1974) by Bill Garnett. Don't you feel like you're a rider? This cover's got a Bradbury vibe for me; also the obligatory reference to surpassing The Exorcist. Yeahhh... no.
Dark Prism by David Lippincott (Dell 1981) Creepy nuns, not quite as popular as creepy kids or clowns, but still up there. This one's particularly effective.
The Midnight Tree by Charles Higham (Pocket 1979) Despite its feyness I dig the mood.
Deadly Eyes by James Herbert (Signet 1983) Movie tie-in edition for Herbert's pulp '70s classic. Meh.
The Other Child by Michael Hale (Avon 1986) Creepy digitalized kid. Fancy and modern!
Saxon's Ghost by Steve Fisher (Pyramid 1972) Psychedelic, we-are-floating-in-space, Stranger In a Strange Land kinda thing. I grok it.
Unholy Child by Catherine Breslin (Signet 1980) Hmm, a pregnant nun? Or not? Or something. Don't think I need to tell you what better books the publisher was trying to evoke.
The Sibling by Adam Hall (Playboy Press 1979) Truly a "What's in the box?!" moment. Don't know what the image has to do with a sibling, though, do you?
Dark Seeker by K.W. Jeter (Tor 1987) Not really sure what's going on here. Anyone?
Owls' Watch (Crest 1965) Delightfully classic vintage horror paperback cover art!
Shadow Child by Joseph A. Citro (Zebra 1987) Damn, this one's no joke. Nice going Zebra!
The Witches by Francois Mallet-Joris (Paperback Library 1970) Great cover art by the Dillons, whose work I was first introduced to through their classic Harlan Ellison covers.
Desecration of Susan Browning by Russell Martin (Playboy Press 1981) Of course this is a Playboy publication.