MacFarlane, Seth
I know him from The Orville; but mostly I know his voice work. Also writing/producing/directing; and singing.
I saw Blue Velvet once, but I don't remember anything about it, and I don't think I cared for it; I've never seen Twin Peaks, but I've always really wanted to, and I'm sure someday I will. I know him from Dune; and Desperate Housewives; and Mysterious Island; several episodes of How I Met Your Mother; and Believe; and Agents of SHIELD; and The Librarian: Quest for the Spear; and The House with a Clock in Its Walls. He also voiced Superman in Justice League: The New Frontier.
Macy, William H.; and Pleasantville; and Mystery Men; and Sports Night; and Bart Got a Room; an episode of Nightmars & Dreamscapes; and Jurassic Park III; and he voiced Satomi in The Wind Rises. And there are probably some other things I don't remember as well...
Maguire, Tobeymovies; and Pleasantville; and The Good German; and The Cider House Rules; and The Ice Storm. Maybe some other stuff.
Malkovich, John, which was really trippy. There's also The Hichhiker's Guide to the Galaxy; and Art School Confidential; and Mary Reilly; and Shadow of the Vampire; and Warm Bodies; and Beowulf; and Crossbones (though I only watched a couple eps of that); and RED. Oh, there's a commercial for iPhone.
Marin, Cheech; and From Dusk till Dawn; and Nash Bridges; and a minor role in Spy Kids; a few episodes of Lost; an episode of Psych; a small role in Race to Witch Mountain; and some voice work.
Marsters, Jamesand Angel. But there was also a recurring role on Smallville; and a couple episodes of Torchwood; and Caprica; and an episode of Warehouse 13; and Dragonball Evolution; and the first ep of the reimagined Hawaii Five-0; and an episode of Supernatural.
McAvoy, James; and The Lion, the Witch and the Wardrobe; and Penelope; and Atonement; a few X-Men movies starting with X-Men: First Class; and Split; and Atomic Blonde; and It Chapter Two; and His Dark Materials
McBrayer, Jack; and Forgetting Sarah Marshall; an episode of New Girl; an ep of The Big Bang Theory; and some voice work.
McBride, Chi; and Pushing Daisies; and Human Target; and an episode of Psych; and Waiting...; and I, Robot; and The Frighteners; and he voiced Nick Fury on Ultimate Spider-Man. I may have seen more of his work, I'm not sure.
McDowell, Malcolm; and Time After Time; and Star Trek: Generations; and Tank Girl; and an episode of Masters of Science Fiction; and an episode of Psych; and a few eps of Community; and Doomsday; and The Company; and a minor role in The Book of Eli; and Princess of Thieves. And he's done some voice work. Plus some Sprint commercials.
McGoohan, Patrick. There's also The Scarecrow of Romney Marsh; and Baby: Secret of the Lost Legend; and voice work in Treasure Planet.
McGrath, Derek. But I also saw him in a few eps of Cheers, an ep of Who's the Boss?, a small role in Northpole: Open for Christmas, and probably some other things I've forgotten. Oh, and I once saw him do a car commercial; I forget what make, but I assume it was German, because there was a really bad pun involving the price $9999 and the word "nein."
McGregor, Ewan; and the Star Wars prequels and the webseries Obi-Wan Kenobi; and Moulin Rouge; and Big Fish; and Emma; and Beauty and the Beast; and Jack the Giant Slayer; and voice work in Robots.
McHale, Joel; and an episode of Video Game High School; and The Great Indoors; and a few eps of The X-Files; and an episode of American Housewife; and Ted.
McKean, Michael; and Clue; and Short Circuit 2; and Saturday Night Live; and an episode of Star Trek: Voyager; and several episodes of The X-Files (and one ep of The Lone Gunmen); and a few eps of Smallville; and an ep of The Good Place; and Good Omens; and Teaching Mrs. Tingle; and surely some other things that I've forgotten.
McKellen, Ian; and the X-Men movies; and the Lord of the Rings movies; and The Prisoner. He also narrated Stardust; and Beauty and the Beast; and voiced Iorek in The Golden Compass; and the Great Intelligence in Doctor Who: The Snowmen. And he's done other stuff I'd like to see.
Meadows, Tim; and The Even Stevens Movie; and Mean Girls; and Son of Zorn; and a few eps of Brooklyn Nine-Nine; and an ep of Miracle Workers; and Aliens in the Attic; and voice work on Bob's Burgers; and probably some things I've forgotten.
Meaney, Colmand Deep Space Nine. But I also know him from The Commitments; and Far and Away; and the pilot episode of Dr. Quinn, Medicine Woman; and The Magical Legend of the Leprechauns; and The Road to Wellville; and probably some other stuff.
Merriman, Ryan; and The Luck of the Irish; and A Ring of Endless Light; and Veritas: The Quest; and Final Destination 3; and A Christmas Movie Christmas.
Miller, Jonny Lee; but there's also Hackers; and Trainspotting; and Dracula 2000; and Dark Shadows; and possibly things I've forgotten.
Miller, Larry; and the TV movie Karroll's Christmas; and a few eps of Boston Legal; and both the movie 10 Things I Hate About You and the TV spinoff; and small roles in Kiss Kiss Bang Bang; and Get Smart; and God Bless America; and The Princess Diaries; and he voiced XR on Buzz Lightyear of Star Command.
Monaghan, Dominic; and the Lord of the Rings movies; and FlashForward; and a minor role in Star Wars: The Rise of Skywalker.
Montalbán, Ricardo, though I remember that but little, from when I was quite young. Plus the "Space Seed" ep of Star Trek, which of course led to the movie Star Trek II: The Wrath of Khan. I also know him from Spy Kids 2. And probably some commercials. I feel like I must've seen him hawking coffee at some point, and of course there's something about "rich Corinthian leather." I dunno. But I'm also a fan of his voice work.
Moranis, Rick; and the Ghostbusters movies; and Strange Brew; and Little Shop of Horrors; and Rocket Boy; and Spaceballs; and Honey I Shrunk the Kids (and its sequel); and voice work in Brother Bear; and the comedy album Great White North; and probably other stuff...
Morgan, Harry; and The Apple Dumpling Gang; and The Wild Wild West Revisited; and The Cat from Outer Space; and likely some things I've forgotten.
Morris, Phil(Jackie Chiles); and a few eps of Terminator: The Sarah Connor Chronicles; and several eps of Smallville (John Jones/Martian Manhunter); and some voice work.
Mumy, Bill; and one of the most memorable episodes of The Twilight Zone ("It's a Good Life"); and Babylon 5.
Murphy, Eddie; and The Golden Child; and Coming to America; and The Haunted Mansion; and he voiced Mushu in Mulan; and Donkey in the Shrek franchise.
Murray, Joel; and Dharma & Greg; and an episode of My Boys; and God Bless America; and Hatchet. Also some voice work, like Carl Bitterman on Baby Blues.
Myers, Mike; and the Wayne's World movies; and the Austin Powers franchise; and So I Married an Axe Murderer; and he voiced the title character in the Shrek franchise; and probably some other stuff. It's all good. (Well, except for The Cat in the Hat, but I'll forgive him for that.)