1st timer over here!

6 sequels (mix-and-match. 6 total):
Gremlins 2: The New Batch, The Texas Chainsaw Massacre 2, Friday the 13th Part 2, Bride of Frankenstein, Bride of Re-Animator, Day of the Dead

6 countries:
Iran/Persian language (A Girl Walks Home Alone At Night), Germany (Trance), Italy (Blood & Black Lace), France (Don't Deliver Us From Evil), USA (Phantom of the Paradise), Japan (Angel's Egg)

6 decades:
30s (Dracula, Bride of Frankenstein, The Black Cat), 40s (Cat People), 50s (The Bad Seed, Diabolique), 60s (Blood & Black Lace, What Ever Happened to Baby Jane?), 70s (Don't Deliver Us From Evil, The Hills Have Eyes, Twins of Evil, Phantom of the Paradise, The Tenant), 80s (The Texas Chainsaw Massacre 2, Friday the 13th Part 2, The Funhouse, Bride of Re-Animator, Day of the Dead, In Just the Wink of An Eye, They Live, Fright Night, Cannibal Holocaust, Angel's Egg, Angst, Ms. 45, White Dog, The Beyond), 90s (Gremlins 2: The New Batch, Army of Darkness) 2000s (A Girl Walks Home Alone at Night)

6 films from before 1970:
Bride of Frankenstein, Dracula, What Ever Happened to Baby Jane, Blood & Black Lace, Cat People, The Black Cat

6 films from the following:
Carpenter (They Live), Raimi (Army of Darkness), Whale (Bride of Frankenstein), Browning (Dracula), Craven (The Hills Have Eyes), Tom Holland (Fright Night) (mix-and-match, or all one)

3 people eating people (non-zombie)
(The Hills Have Eyes, Cannibal Holocaust, Trance)

1 Hammer Film
(Twins of Evil)

1 Romero Dead film
(Day of the Dead)

1 terrible oversight
(Diabolique)

2 Tobe Hooper
(The Texas Chainsaw Massacre 2, Eggshells)

Bonus: Both "IT" films