A few I'd recommend are......
Blood On Satan's Claw
Nothing But the Night
I Walked with a Zombie
White Zombie
The Serpent and the Rainbow
Night of the Eagle
Night of the Demon (50's occult thriller, not Reaper's fave
)
The Devil Rides Out
Curse of the Crimson Altar
Rosemary's Baby
Race with the Devil
Brotherhood of Satan
The Devil's Rain
The Ninth Gate
The Mephisto Waltz
The Witches
The Wicker Man
To The Devil... A Daughter
City of the Dead
Suspiria
Inferno
Warlock
The Perfume of the Lady in Black
The Seventh Victim
Tales That Witness Madness (final segment)
I've deliberately excluded The Devils, Mark of the Devil and Witchfinder General, as they're focused on historical events and on religious mania rather than down to any real occultic influence. Although The Devils could be seen as a bit ambiguous in this regard.