Dark musicals are musicals that feature horror, supernatural, science fiction, and/or other strange plot elements.  Some take the genres they represent very seriously and others are tongue-in-cheek parodies.  Most have small but devoted fan bases and have become cult favorites.  Below is an extensive and constantly growing list.  Click a show for blog posts relating to it.

The Addams Family (Lippa)
Assassins (Sondheim)
Autumn Moon (Velarde)
Bat Boy (O’Keefe) 
Buffy the Vampire Slayer: Once More With Feeling (Whedon)
Bunkerville: A Post-Apocalyptic Musical (Sonnenblick) 
Buzzsaw Berkeley (LaChiusa)
Cannibal! The Musical (Parker/Stone)
Carrie: The Musical (Gore)
Casper: The Musical (Marsh, Pickett)
The Change: Another Teen Werewolf Musical (Frampton)
Clue: The Musical (Blum, Barker, Martucci) 
Corpse Bride (Elfman)
The Count of Monte Cristo (Wildhorn)
The Craft: The Musical (Jones)
Creature from the Black Lagoon (Barton)
The Crucible: The Opera
Der Glöckner von Notre Dame (Menken)
Dorian Gray (Multiple versions)
Dr. Horrible’s Sing-Along Blog (Whedon)
Dracula (Svoboda) 
Dracula (Wildhorn) 
Eating Raoul (Feuer)
Escape from Pterodactyl Island (Morris) 
Evenings in Quarantine: The Zombie Opera (Bogovich/Rishel)
Evil Dead: The Musical (Cipolla, Bond)
Faust (Newman)
Faustus (Mott)
The Fly: The Opera (Shore)
Frankenstein: The Musical (Baron)
Gay Bride of Frankenstein (Butler)
Ghost: The Musical (Stewart/Ballard)
Grail: The Sci-Fi Rock Musical (Christianson) 
Great White Shark: The Musical (Sutherland)
Halloween Hullabaloo (Winegardner)
Halloween: The Musical (DeHaas)
Heathers: The Musical (O’keefe)
Hocus Pocus (Hawkins/Horner) 
Human Centipede: The Musical (Mattison)
I Kissed a Vampire (Blue)
Into the Woods (Sondheim)
Jack the Ripper (multiple versions)
Jerry Springer: The Opera (Thomas/Lee)
Jekyll & Hyde (Wildhorn)
Jonestown: The Musical (Lees) 
The Last Starfighter (Kennon)
The Legend of Sleepy Hollow (Crowley)
Lestat (John)
Little Shop of Horrors (Menken)
Lizzie Borden: A Musical Tragedy in Two Axe (McGovern/Powers)
Love Never Dies (Webber) 
Meathook: A Melodrama (Prince/Fontaine)
Mythos: The Crimson Chorus (Velarde) 
Nevermore (Conner)
A New Brain (Finn)
Next To Normal (Kitt)
Nightmare Before Christmas (Elfman)
Night of the Living Dead: The Musical (Conner/Smith) 
The Phantom of the Opera (Webber)
Phantom of the Paradise (Williams)
Poultrygeist: Night of the Chicken Dead (Banas)
Rebecca (Levay)
REEFER MADNESS (Studney)
Repo! The Genetic Opera (Zdunich, Smith)
Return to the Forbidden Planet (Various)
The Rocky Horror Picture Show (O’Brien/Hartley)  
Ruthless! (Laird) 
The Scarlet Pimpernel (Wildhorn)
Scarrie! The Musical (Cerda/Lamberty/Ross)
SCREAM, The Musical (Snow) *Not full show
Shockheaded Peter (Huge, Jacques, Stout)
Side Show (Kreiger) 
Silence! The Musical (Kaplan)
Song of the Living Dead (Frampton)
Spring Awakening (Sheik)
Starmites (Keating) 
Starship: The Musical (Criss)
Star Wars: The Musical (Nolen, Smith)
Svengali (Wildhorn) 
Sweeney Todd (Sondheim)
Tanz der Vampire (Steinman)
A Tale of Two Cities (Santoriello)
Teen Witch: The Musical (Elliot)
Texas Chainsaw Musical (Bytof)
Thrill Me (Dolginoff) 
Time (Clark, Daniels) 
The Toxic Avenger (Bryan)
Twilight: The Musical (Lewis)
Urinetown (Hollmann) 
Via Galactica (MacDermot) 
Voyage of the Rock Aliens (White) 
The Witches of Eastwick (Rowe)
Weird Romance (Menken) 
Which Witch (Adrian)
Wicked (Schwartz)
The Woman In White (Webber)
Young Frankenstein (Brooks)
Zombie Prom (Rowe)
Zombies From the Beyond (Valcq)
Z-Town: The Zombie Musical (Rose)
*Misc Shows/Songs