THIS IS A VERY OLD AND INCOMPLETE FIRST VERSION OF THE LIST.

SEE THE NEW VERSION HERE (en.gregoryrozek.com/supernatural-episodes-guide)

Key plot episode

1×01 Pilot

1×02 Wendigo
1×03 Dead in the Water
1×04 Phantom Traveller
1×05 Bloody Mary
1×06 Skin
1×07 Hook Man
1×08 Bugs
1×09 Home
1×10 Asylum
1×11 Scarecrow

1×12 Faith
1×13 Route 666
1x14 Nightmare

1×15 The Benders
1×16 Shadow
1×17 Hell House
1×18 Something Wicked
1×19 Provenance
1×20 Dead Man’s Blood
1×21 Salvation
1×22 Devil’s Trap
2×01 In My Time of Dying
2×02 Everybody Loves a Clown
2×03 Bloodlust
2×04 Children Shouldn’t Play With Dead Things
2×05 Simon Said
2×06 No Exit
2×07 The Usual Suspects
2×08 Crossroad Blues
2×09 Croatoan

2×10 Hunted
2×11 Playthings
2×12 Nightshifter
2×13 Houses of the Holy
2×14 Born Under a Bad Sign
2×15 Tall Tales

2×16 Roadkill
2×17 Heart
2×18 Hollywood Babylon
2×19 Folsom Prison Blues
2×20 What Is and What Never Should Be
2×21 All Hell Breaks Loose
(Parts 1 & 2)

3×01 The Magnificent Seven
3×02 The Kids Are Alright
3×03 Bad Day at Black Rock

3×04 Sin City
3×05 Bedtime Stories
3×06 Red Sky at Morning
3×07 Fresh Blood
3×08 A Very Supernatural Christmas
3×09 Malleus Maleficarum
3×10 Dream a Little Dream of Me
3×11 Mystery Spot

3×12 Jus in Bello
3×13 Ghostfacers
3×14 Long Distance Call
3×15 Time Is on My Side
3×16 No Rest for the Wicked
4×01 Lazarus Rising
4×02 Are You There, God? It’s Me, Dean Winchester
4×03 In the Beginning
4×04 Metamorphosis
4×05 Monster Movie
4×06 Yellow Fever
4×07 It’s the Great Pumpkin, Sam Winchester
4×08 Wishful Thinking
4×09 I Know What You Did Last Summer
4×10 Heaven and Hell
4×11 Family Remains
4×12 Criss Angel Is a Douchebag
4×13 After School Special
4×14 Sex and Violence
4×15 Death Takes a Holiday
4×16 On the Head of a Pin
4×17 It’s a Terrible Life
4×18 The Monster at the End of This Book
4×19 Jump the Shark
4×20 The Rapture
4×21 When the Levee Breaks
4×22 Lucifer Rising
5×01 Sympathy for the Devil
5×02 Good God, Y’All!
5×03 Free to Be You and Me
5×04 The End
5×05 Fallen Idols
5×06 I Believe the Children Are Our Future
5×07 The Curious Case of Dean Winchester
5×08 Changing Channels
5×09 The Real Ghostbusters
5×10 Abandon All Hope…
5×11 Sam, Interrupted
5×12 Swap Meat
5×13 The Song Remains the Same
5×14 My Bloody Valentine
5×15 Dead Men Don’t Wear Plaid
5×16 Dark Side of the Moon
5×17 99 Problems
5×18 Point of No Return
5×19 Hammer of the Gods
5×20 The Devil You Know
5×21 Two Minutes to Midnight
5×22 Swan Song
6×01 Exile on Main St.
6×02 Two and a Half Men
6×03 The Third Man
6×04 Weekend at Bobby’s
6×05 Live Free or Twihard
6×06 You Can’t Handle the Truth
6×07 Family Matters
6×08 All Dogs Go to Heaven
6×09 Clap Your Hands If You Believe…
6×10 Caged Heat
6×11 Appointment in Samarra
6×12 Like a Virgin
6×13 Unforgiven
6×14 Mannequin 3: The Reckoning
6×15 The French Mistake
6×16 …And Then There Were None
6×17 My Heart Will Go On
6×18 Frontierland
6×19 Mommy Dearest
6×20 The Man Who Would Be King
6×21 Let It Bleed
6×22 The Man Who Knew Too Much
7×01 Meet the New Boss
7×02 Hello, Cruel World
7×03 The Girl Next Door
7×04 Defending Your Life
7×05 Shut Up, Dr. Phil
7×06 Slash Fiction
7×07 The Mentalists
7×08 Season Seven, Time for a Wedding!
7×09 How to Win Friends and Influence Monsters
7×10 Death’s Door
7×11 Adventures in Babysitting
7×12 Time After Time
7×13 The Slice Girls
7×14 Plucky Pennywhistle’s Magical Menagerie
7×15 Repo Man
7×16 Out with the Old
7×17 The Born-Again Identity
7×18 Party On, Garth
7×19 Of Grave Importance
7×20 The Girl with the Dungeons and Dragons Tattoo
7×21 Reading Is Fundamental
7×22 There Will Be Blood
7×23 Survival of the Fittest
8×01 We Need to Talk About Kevin
8×02 What’s Up, Tiger Mommy?
8×03 Heartache
8×04 Bitten
8×05 Blood Brother
8×06 Southern Comfort
8×07 A Little Slice of Kevin
8×08 Hunteri Heroici
8×09 Citizen Fang
8×10 Torn and Frayed
8×11 LARP and the Real Girl
8×12 As Time Goes By
8×13 Everybody Hates Hitler
8×14 Trial and Error
8×15 Man’s Best Friend with Benefits
8×16 Remember the Titans
8×17 Goodbye Stranger
8×18 Freaks and Geeks
8×19 Taxi Driver
8×20 Pac-Man Fever
8×21 The Great Escapist
8×22 Clip Show
8×23 Sacrifice
9×01 I Think I’m Gonna Like It Here
9×02 Devil May Care
9×03 I’m No Angel
9×04 Slumber Party
9×05 Dog Dean Afternoon
9×06 Heaven Can’t Wait
9×07 Bad Boys
9×08 Rock and a Hard Place
9×09 Holy Terror
9×10 Road Trip
9×11 First Born
9×12 Sharp Teeth
9×13 The Purge
9×14 Captives
9×15 #THINMAN
9×16 Blade Runners
9×17 Mother’s Little Helper
9×18 Meta Fiction 
9×19 Alex Annie Alexis Ann
9×20 Bloodlines
9×21 King of the Damned
9×22 Stairway to Heaven
9×23 Do You Believe in Miracles
10×00 A Very Special Supernatural Special (a behind-the-scenes look at all past seasons)
10×01 Black
10×02 Reichenbach
10×03 Soul Survivor
10×04 Paper Moon
10×05 Fan Fiction
10×06 Ask Jeeves
10×07 Girls, Girls, Girls
10×08 Hibbing 911
10×09 The Things We Leave
10×10 The Hunter Games
10×11 There’s No Place Like Home
10×12 About a Boy
10×13 Halt & Catch Fire
10×14 The Executioner’s Song
10×15 The Things They Carried
10×16 Paint It Black
10×17 Inside Man
10×18 Book of the Damned
10×19 The Werther Project

10×20 Angel Heart
10×21 Dark Dynasty
10×22 The Prisoner
10×23 Brother’s Keeper

11×01 Out of the Darkness, Into the Fire
11×02 Form and Void
11×03 The Bad Seed
11×04 Baby
11×05 Thin Lizzie
11×06 Our Little World
11×07 The Bad Seed
11×08 Baby
11×09 O Brother Where Art Thou?
11×10 The Devil In The Details
11×11 Into the Mystic
11×12 Don’t You Forget About Me
11×13 Love Hurts
11×14 The Vessel
11×15 Beyond the Mat
11×16 Safe House
11×17 Red Meat
11×18 Hell’s Angel
11×19 The Chitters
11×20 Don’t Call Me Shurley
11×21 All In The Family
11×22 We Happy Few
11×23 Alpha And Omega

After the ridiculous writing of the season 11, the season 12 is fresh and better quality in my opinion. I recomend watching all episodes.

12×01 Keep Calm And Carry On
12×02 Mamma Mia
12×03 The Foundry
12×04 American Nightmare
12×05 The One You’ve Been Waiting For [Nazi theme]
12×06 Celebrating the Life of Asa Fox
12×07 Rock Never Dies
12×08 LOTUS
12×09 First Blood
12×10 Lily Sunder Has Some Regrets
12×11 Regarding Dean
12×12 Stuck in the Middle (With You)
12×13 Family Feud
12×14 The Raid
12×15 Somewhere Between Heaven and Hell
12×16 Ladies Drink Free
12×17 The British Invasion
12×18 The Memory Remains
12×19 The Future
12×20 Twigs & Twine & Tasha Banes
12×21 There’s Something About Mary
12×22 Who We Are
12×23 All Along the Watchtower

Based on: http://interplosion.com/topic539.html, reviewed, corrected and expanded by Gregory