Calling a day on the following. I'm listing three movies. Name the actor (in gender neutral sense) who was in all three:
4. Rocky, Terror Firmer, Orgazmo
5. Night at the Golden Eagle, Rules of Attraction, The One-Eyed Monster
6. Shrek 2, Die Another Day, The Adventures of Pluto Nash
10. The Barber, The Cat People, Blue Thunder
11. The Coca-Cola Kid, The Expendables, Star 80
14. From Dusk Till Dawn, A Very Harold and Kumar Christmas, Rise of the Zombies
17. SpiderBabe; Splatter Beach, Shadow: Dead Riot
20. The Return of the Living Dead, Night of the Demons, Still Smokin

Andy E. Nystrom wrote:

1. American Graffiti, Working Girl, Witness
4. Cannibal! The Musical, Team America: World Police, Bowling for Columbine
8. The Return of Captain Invincible, Serial, Horror of Dracula
9. Home Alone 2: Lost in New York, Ghosts Can't Do It, POM Wonderful Presents: The Greatest Movie Ever Sold
10. Blow-Out, Pulp Fiction, Bolt
14. Blade Runner, Young Doctors in Love, Love Crimes
16. Dracula, The Devil Bat, Plan 9 from Outer Space
17. The Terror, The Little Shop of Horrors, Carnal Knowledge
19. Manon des sources, La Belle Noiseuse, Mission: Impossible
23. Can't Stop the Music, Diner, 3 Men and a Little Lady
24. Flatliners, Phone Booth, Flashback
 

1. Harrison Ford
4. Charlton Heston?
8. Christopher Lee?
9. Donald Trump?
10. John Travolta?
14. Sean Young?
16. Bela Lugosi
17. Jack Nicholson
19. Emmannuelle Beart?
23. Steve Guttenberg?
24. Kiefer Sutherland

Calling a day on the following (three movies sharing one actor; some docs included)
2. The Man Who Haunted Himself, Spice World, The Cannonball Run
3. The Toxic Avenger Part II, Terror Firmer, Poultrygeist: Night of the Chicken Dead
4. Cannibal! The Musical, Team America: World Police, Bowling for Columbine
5. This is Spinal Tap, Body Double, Scream Queen Hot Tub Party
6. Avengers: Age of Ultron, Avengers: Infinity War, Martha Marcy May Malone
7. The Amityville Horror, Black Christmas, Confessions of a Superhero
11. Def by Temptation, The Spirit, Resurrecting the Champ
12. Freddy's Dead: The Final Nightmare, Private Resort, Dead Man
13. Tapeheads, Noise, Fraternity Vacation
15. Baadasssss!, The Happy Hooker Goes Hollywood, Batman: The Movie
18. The Re-Animator, Chopping Mall, Castle Freak
20. Friday the 13th: The Final Chapter, License to Drive, Citizen Toxie: The Toxic Avenger IV
21. Troma's War, The Toxic Avenger Part III: The Last Temptation of Toxie, Bigger Stronger Faster*
22. Sgt. Kabukiman N.Y.P.D., Class of Nuke 'Em High Part II: Subhumanoid Meltdown, Class of Nuke 'Em High Part 3: The Good, the Bad and the Subhumanoid
25. The Cool Surface, Heaven's Prisoners, Tomorrow Never Dies

6 is correct.

As with TV shows, doing movie characters in their own words. As not all movies are serialized, some of these are non-recurring but still prominent. Name the character and the movie or movie franchise. Some characters might be fictionalized versions of real people. As before not everyone is a reliable narrator.

1. I'm a supernatural killer who likes to [BLEEP] with people before I kill them. I'm often hidden in plain sight. In the course of my adventures I gain a family.

2, I don't know who I am. I don't have amnesia; I'm just one of many faceless business people. What maybe does make me stand out a bit is my love of popular music. Oh, and I occasionally kill people to give myself some release.

3. I'm a suburbanite with a spouse and two teenage children. If people annoy me I might harass them with annoying prank calls, or if they really do something against common sense rules, I might just kill them.

4. I am from a faraway land and have special abilities. I left the land during a major world conflict at the start of the 20th century to help the side I felt was in the right, and have continued to help people in the century that followed. In recent times I joined a team of like minded people.

5. I was a mobster at the top of my game. My organization was about to make a major deal with mobsters from another country. But then I had a very long bad day where something happened to piss off terrorists and they really started making a mess of things. The cowards from that other country pulled out as I tried to find out what pissed off the terrorists.

6. I have a trained assassin who killed people with his teeth. I have a soft side that I never show my victims and it's possible that the right woman might be able get me to change my ways.

7. I am a prominent world leader and warmonger. There is a lookalike out there who is a pacifist. I like to play with an inflatable replica of the Earth.

8. I was a reckless person from another world. My stepbrother was more manipulative than I realized and I got sent to your world due to his trickery.  There my abilities were limited for a time because I was deemed unworthy.

9. I am a movie police officer who's been on a number of tough missions. A kid brought me to the real world, but one of my enemies also joined me there.

10. I was a janitor who got dumped into a vat of nuclear waste. I was transformed into an evil fighting monster, living my home location's landfill.

11. I was born to a travelling circus. I have body parts that are larger than most and I use those to fly even though that's impossible for others of my type.

12. I am an elderly person transformed by aliens into a ghoul. When the mood strikes me I hold my cape over my face to hide my features.

13. I'm an upbeat person with a song in my heart leading a group of gold prospectors. When my horse left me (I'm sure not of her own free will; she wouldn't do that), I starting making finding her a priority, something I hid from the group. They wouldn't understand.

14. I'm a kid trained by my wonderful daddy to kill bad guys. I've met another hero. I'd best help him because although older than me, he's in way over his head.

15. I'm a very healthy person, never gotten sick, have survived a lot of dangerous things. I could drown though. A comic book fanatic has taken a strange interest in me lately.

16. I'm a movie actor, very method. In my latest role I got made to look like a black man, not traditional blackface, something more realistic. And dig it, I've started talking like a sitcom black character even though I'm a honky in real life. Somehow me and some other actors, we've found ourselves under attack. If this is still part of the movie, the effects have gotten a lot more realistic.

17. Some would call me a killer. I'm not. I abhor killers. But I don't have long to live so I've decided to teach people a lesson. I put them in traps. They can easily escape by learning a really painful lesson about their wrongdoings. If they die it's not my fault; they weren't willing to change.

18. I'm a vigilante seeking the super-villain who killed my mother. I've recently befriended a prostitute. She won't admit it but she's actually really nice. I thought I had no powers but a bad guy shot me and I was okay so I must have powers after all, at least I can't be hurt.

19. I live in a small town and, I admit it, I came on too strong with a woman and she bit me. I become like her and her group and I'm doing my best to stay alive (her group doesn't like me very much, though they're trying to teach me) but at the same time I don't want to kill anyone like they want me too.

20. I'm an undead military commander from a long ended conflict. I don't speak. Some youth in a cabin found our gold so it's time to get it back. And kill them of course. Maybe we'll invade another country afterwards.
 

Those are correct; for 9 the character is still needed. Let's see if anyone remembers 16's name.

2 Beverly, Serial Mom
14 Hit Girl, Kick Ass
15 David Dunn, Unbreakable
17 Jigsaw, Saw
19 Caleb, Near Dark

1 Michael Myers, Halloween?
7 Adenoid Hynkel, Great Dictator
12 Old Man, Plan 9 from Outer Space

Andy E. Nystrom wrote:

1 is incorrect. While we learn about a family connection later in the series, Michael doesn't actually gain family members. And while he's very stealthy, he can't really be in plain sight without raising alarms.

The other two are correct. The cape bit of course for Plan 9 was to try to hide the fact that the actor was no longer the late Bela Lugosi.

1 Chucky, Chucky?

Clearing out the fully answered ones:

5. I was a mobster at the top of my game. My organization was about to make a major deal with mobsters from another country. But then I had a very long bad day where something happened to piss off terrorists and they really started making a mess of things. The cowards from that other country pulled out as I tried to find out what pissed off the terrorists.

6. I have a trained assassin who killed people with his teeth. I have a soft side that I never show my victims and it's possible that the right woman might be able get me to change my ways.

9. I am a movie police officer who's been on a number of tough missions. A kid brought me to the real world, but one of my enemies also joined me there.
[Partly answered: Arnold's character in The Last Action hero]

13. I'm an upbeat person with a song in my heart leading a group of gold prospectors. When my horse left me (I'm sure not of her own free will; she wouldn't do that), I starting making finding her a priority, something I hid from the group. They wouldn't understand.

16. I'm a movie actor, very method. In my latest role I got made to look like a black man, not traditional blackface, something more realistic. And dig it, I've started talking like a sitcom black character even though I'm a honky in real life. Somehow me and some other actors, we've found ourselves under attack. If this is still part of the movie, the effects have gotten a lot more realistic.
[Partly answered: Robert Downey Jr's character in Tropic Thunder]

18. I'm a vigilante seeking the super-villain who killed my mother. I've recently befriended a prostitute. She won't admit it but she's actually really nice. I thought I had no powers but a bad guy shot me and I was okay so I must have powers after all, at least I can't be hurt.

20. I'm an undead military commander from a long ended conflict. I don't speak. Some youth in a cabin found our gold so it's time to get it back. And kill them of course. Maybe we'll invade another country afterwards.

9 is correct.

18 is correct.

Arthur has a cognitive disability. He is not invulnerable; the person who shot him was an undercover cop who shot blanks. He's also wrong about it being a super-villain who killed his mother; what he misheard as Captain Industry was actually "the captains of industry".

6 Jaws, Moonraker (if we're taking the bit about the right woman making him change his ways).

 

Answers:

5. I was a mobster at the top of my game. My organization was about to make a major deal with mobsters from another country. But then I had a very long bad day where something happened to piss off terrorists and they really started making a mess of things. The cowards from that other country pulled out as I tried to find out what pissed off the terrorists.
ADD: It was a holiday where everything went wrong

Harold Shand, The Long Good Friday

13. I'm an upbeat person with a song in my heart leading a group of gold prospectors. When my horse left me (I'm sure not of her own free will; she wouldn't do that), I starting making finding her a priority, something I hid from the group. They wouldn't understand.
ADD: I've been arrested. A reporter is really good at getting me to tell her things about my case before my trial.

Alferd Packer (fictionalized), Cannibal! The Musical

His horse Liane left him willingly.

16. I'm a movie actor, very method. In my latest role I got made to look like a black man, not traditional blackface, something more realistic. And dig it, I've started talking like a sitcom black character even though I'm a honky in real life. Somehow me and some other actors, we've found ourselves under attack. If this is still part of the movie, the effects have gotten a lot more realistic.
ADD: My last name refers to someone who came back from the dead.
[Partly answered: Robert Downey Jr's character in Tropic Thunder]

Kirk Lazarus

20. I'm an undead military commander from a long ended conflict. I don't speak. Some youth in a cabin found our gold so it's time to get it back. And kill them of course. Maybe we'll invade another country afterwards.
ADD: One of my enemies switched an arm with one of mine and is raising his own army against mine.

Herzog, Dead Snow movies

2. 2001 and 2010
3. 1941
4. 12 Angry Men
5. 10
8. 300
9. 28 Weeks Later
11. Star 80
14. 2012?
16. Ocean's 11 (should be Rat Pack)
18. Se7en
20. Super 8