Bit clueless when it comes to horror, but I've had a go.
Vampyr (Carl Theodor Dreyer)
Kuroneko (Kaneto Shindô)
Eyes Without a Face (Georges Franju)
Psycho (Alfred Hitchcock)
The Cabinet of Dr. Caligari (Robert Wiene)
Suspiria (Dario Argento)
Tetsuo, the Iron Man (Shin'ya Tsukamoto)
A general list's far easier to populate, but much more difficult to narrow down to 10.
Le samouraï (Jean-Pierre Melville)
The Fire Within (Louis Malle)
Vertigo (Alfred Hitchcock)
Un homme qui dort (Bernard Queysanne)
Ugetsu (Kenji Mizoguchi)
Stalker (Andrei Tarkovsky)
Werckmeister Harmonies (Béla Tarr, Ágnes Hranitzky)
The Seventh Seal (Ingmar Bergman)
Rififi (Jules Dassin)
Army of Shadows (Jean-Pierre Melville)
Ponderous, contemplative silliness in abundance, I'm afraid. Would've liked to have linked my lists from mubi/the auteurs, but the profile's in private mode atm.