While an attempt has been made to be as comprehensive as possible in the Science Fiction Index, a line had to be drawn somewhere and there are a number of titles you might expect to find here which have been deliberately excluded. These fall into four major categories:
The original index compiled by Stephen T. Miller and William G. Contento was created at a time when few other "genre" indexes had been written and, as such, indexed a number of "fringe titles", particularly in the "hero pulp" and "weird menace" fields, which has some elements of SF but do not really qualify as science fiction, fantasy or weird fiction. As these have now been fully indexed elsewhere, particularly in the Crime Fiction Index and the Adventure Fiction Index there seems no need to repeat them in this index. The titles concerned are:
The original index also contained a number of magazines which typically contained little or no SF, but which published special SF issues, or which had some related connection to the genre. In many cases other issues of the same magazine are already indexed in the Fictionmags Index so it seems sensible to exclude those magazines from this index as well. The titles concerned are:
The SFFWF field is an incredibly prolific one and there are (literally) an unknown number of minor magazines, ranging from the fanzines of the 1930s to the online magazines of the 2010s, many of which have not even been catalogued, let alone indexed. In some cases, partial listings of these titles are available in the Fictionmags Index while in others little is known beyond the magazine title and rough publication details. Over time, hopefully, some of these titles will be fully indexed and will be added to the Science Fiction Index, but, for now, the following titles have been excluded:
| Abortions | Duckspeak | Labyrinth Inhabitant | Scienti-Comics |
| Absent Willow Review | Ecce | Lakeside Circus | Scifaikuest |
| Ad Astra [1965] | Eclipse [1966] | Laser & Sword Magazine | SciFi Dimensions |
| Adbhut | Eclipse [1970] | Lathered in Crimson | SciFi Freedom |
| Afterburn SF | Edge of Twilight | Laughing Osiris | SciFi Paradox |
| Agog | eFantasy | Leprechaun | Sci-Fi Short Story Magazine |
| Aleph-Null | Eldritch Science | Les Spinge | Scorched Earth |
| Alien Culture | Electric Wine | Lethe | Scream Queens Illustrated |
| Alien Landings | Elegia | Lighthouse [1960s] | SDO Fantasy |
| Alien Skin | 1130 Club | The Little Corpuscle | Senary |
| alphaDrive | Elysian Fiction | The Looking Glass | Sentinel SF |
| Altair [1950] | Embelyon | The Lorelei Signal | Serpentarius |
| Altered Reality | Empire for the SF Writer | Lost Pages | Seventh Dimension |
| Alternate Realities | Entropy | Lost Worlds | The Seventh Seal |
| Alternaties | Erotic Horror & Fantasy Magazine | Lovecraftiana | Severed Tales |
| Alternative Coordinates | Escape [1930s] | Low Orbit | SFanzine |
| Anomaly | Escape Velocity | Lunar Castles | Shadowdance |
| Anotherealm | Eternity | Macabre Tales | Shadowland [1950s] |
| Antares | Ethereal Gazette | Mad Scientist Journal | Shadowland [1990s] |
| Anthro | Eulogy | Mainstream | Shiny |
| Antithesis [1973] | Eusifanso | The Many Worlds of Jack Vance | Shiver |
| Apocalypse Fiction | Event Horizon [1987] | Maplecade | Si-Fan |
| Appalling Stories | Exile [1960s] | Marginal Boundaries | Silver Blade |
| Arcana | Expressions of Dread | Mars! | Simulacrum |
| Arioch | Extro [1980] | The Marvellous Magazine | Sinfully Twisted |
| Arkham Tales | Eye of Newt | The Masked Spaceman | Sinister Tales |
| Art & Story | Eye to the Telescope | Masque (UK) | Skewed |
| ASFO | Fabulist [2009] | Meshuggah | Sky Hook |
| Asmodeus [1969] | Fadaway | Midnight Wine | S1ngularity |
| Astonishing Stories [1935] | Fairy Tale Review | Mindflights | The Sockdolager |
| Astounding Tales | Fanatic | Mindscapes | Sol Reader |
| Athene | Fandom Unlimited | Mirage | Sonar4 |
| Atomjack | Fanomena | Miriad | Sorcerous Signals |
| Aurora Speculative Feminism | Fan Slants | Mirth and Irony | The Southern Star |
| Auslander | Fantasia [1941] | The Miskatonic | Space Gamer/Fantasy Gamer |
| Avatar | Fantasia [1951] | Modern Mythology | Spaceports and Spidersilk |
| Avesta | Fantasite | Monomyth | Space Squid |
| Banana Skins | Fantast Sidetrack | The Monsters Next Door | Spacesuits and Sixguns |
| Banana Wings | Fantasy Annual [1948] | Moondust | Spaceship |
| Bane | Fantasy Collector's Annual | Morgan Smith | Space Tales |
| The Banshee | Fantasy Digest | Moslem in Cambridge | Spaceteer |
| Barbarian Scroll | Fantasy Fiction Field | The Multiversal Scribe | Spaceways [1938] |
| Bardic Runes | Fantasy Jackpot | Multiverse Magazine | Spaceways [1996] |
| The Barsoomian | Fantasy Times | Muse Fantastique | Spearhead |
| Bar Trek | Fantazone | Muzzy | Spectra-Foundation SF & Fantasy Mag |
| Basement Stories | Fanvariety | Mystic Signals | Spectra Magazine |
| Beabohema | Farrago | Mythagoras | Speculation |
| Betelgeuse | Fear and Trembling Magazine | Mythos | Speculative Fiction and Beyond |
| Bête Noire | FemSpec | The NASFA Shuttle | Speculon |
| Bewildering Stories | Fiction Inferno | Nebula [1950] | The Specusphere |
| Beyond [1943] | Fifth Di... | Nebula [1970] | SPGA Showcase |
| Beyond the Moon | Flapperhouse | Necrography | Staffs and Starships |
| Bite Me Magazine | Flash Fantastic! | Necrophantasy | The Stake |
| Black Flames | Flashing Swords | Neometropolis | The Standing Stone |
| Black Hole | Fogfire | Neverary | Stardust [1960s] |
| The Black Lily | Foma | Neverworlds | Starlight |
| Black Moon | Fools Motley Magazine | New Realm | Starlit Fantasy |
| Black Oracle | Fortean Bureau | New Venture [1975] | Steampunk Tales |
| Black Skull Magazine | Foundation | New Witchcraft | Stellarite |
| Blood from 'Stones | Foxfire | New Words | STFanatic |
| Bloodlines | Franson's | Next Phase | Stone Telling |
| Bloodrake | Freedom Fiction Journal | Nexxus | Straitjacket |
| The Blue Lady | F(r)iction | Night Dreams | Strange Aeons [1990s] |
| Bone Chilling Tales | FTL Science Fiction | The Nightmare Express | Strange Aeons [2010] |
| Bone Marrow Review | Full Moon S.F. | Nightmares Quarterly | Strange Brew |
| Brain Harvest | Fusion Fragment [2007] | Nightside | Strange, Weird and Wonderful Magazine |
| Brillig | Future Focus | Night to Dawn | Strange Wonderland |
| Bulletin of Terrestrial Fantascience Guild | Futurian War Digest | Night Views | Strix |
| Burroughs Bulletin | Futurismic | Nightworld | The Stylus [1993] |
| Byzarium | Garage Floor | Niteblade | Styx |
| Cabal Asylum | Gathering Darkness | The Nocturnal Lyric | Sumer Morn |
| Cactus | Gauntlet! The Magazine of Heroic Tales | Nomad | Sun Spots |
| Camber | genrEzone | Not at Night | Surprising Stories |
| Canadian Fandom | Giallar | Nova [1941] | The Sword Review |
| Canticles from Labowitz | Glutonlumps Chilling Tales | Nova [1972] | Swords and Sorcery Magazine |
| Catenary Tales | Goblin Fruit | Nova [1989] | Symphonie's Gift |
| Cats with Wings | Golana | Novae Terrae | Syzygy |
| Cemetery Moon | Golden Atom | The Nucleus | Tabebuian |
| Censored | Golden Visions Magazine | Nuketown | Talers Tales |
| Centauri | Goodwitch Stories | Nu Ormenel Collected | Tales from Texas |
| Challenger | Gothic Light | Odd Tales of Wonder Magazine | Tales of Blood and Roses |
| Chanticleer | Granfalloon | Of Unicorns and Space Stations | Tales of Horror and Damnation |
| Chaos Theory: Tales Askew | Graveyard Rendezvous | Ogre | Tales of the Episco Pals |
| The Chigger Patch of Fandom | Grimoire [1993] | Old Bones | Tales of the Grotesque and Arabesque |
| Chimaeran Review | Grok | Omnifan | The Tale Spinner |
| Chronicle | The Grotesque [1940s] | Omni Online | Tangent [1976] |
| Ciln | Grue [1953] | The Oracle [1982] | Terraform |
| Cinquefoil | Gryffon's Star | Orion Science Fiction | Terror |
| Citadel | Grymalkin | The Orphic Chronicle | Terror Hunters Journal |
| The City Morgue | Gryphonwood | Ouroboros | The Thing |
| Clarges | Hands in the Dark | The Outlander | Third Order |
| The Comet (fnz) | Harbinger [1975] | Outside | Thirteen Magazine |
| The Communicator | The Hardcore | Outsider | This Way Up |
| Concept Sci-fi E-zine | Harsh Reality | Pages [1988] | Tiamat |
| Cosmic Speculative Fiction | Haunted Journal | Pan Demos | TiconderogaOnline |
| Coyote Wild | Heart Attack | Pantechnicon | Time Travel Tales |
| Crabapple | Heliocentric Net | Papyrus [1999] | Tiofart |
| Crifanac | Heliophobe | Paradox [1942] | TLMA |
| Cyberpulp Magazine | Heliotrope | Parageography | Tomorrow Magazine [1970] |
| Cygni | Hocus | Parlour Papers | Toward Tomorrow |
| The Cygnus Chronicler | Holier Than Thou | Pegasus Online | Tower of Light |
| The Daily Phantagraph | Horizons (fnz) | Peridot Books | Trail of Indiscretion |
| Damned Thing | Horrorfest | The Periodical Lungfish | Transmission |
| Dark Energy | The Horror Fiction Review (fnz) | Phantasia | Troat |
| Dark Infinity | The Horror Zine | Phenomena | The Tryout |
| Dark Moon Rising | The H.P. Lovecraft Fanzine | Phile | TSAT (Transformation Stories) |
| Dark Muse | Hugin and Munin | Piffle | Twilight Garden |
| Dark's Art Parlour | Hyphen [1952] | Planet Magazine | Twilight Times |
| Dark Side | Ibidem | Planet Relish | Twin Cities SF & Fantasy Magazine |
| Dark Star | Ibn Qirtaiba | Pluto | Twisted Dreams Magazine |
| Dark Tome | If! (fnz) | Polaris [1940] | Ultraverse |
| Dark Visions | IFA Review | Polaris [1980] | Undinal Songs |
| Darwin's Evolutions | Illumen | Polluto | Universe Pathways |
| Daughters of Nyx | Imagination [1971] | Popular Music & Science-Fiction Journal | Usok |
| Dead Letters | Imagination [1990s] | Pornographic Onion | Usva International |
| Deadspawn | Imaginative Fiction | Port Iris | Utopian |
| Demensions | Incredible | Procyon | Vamperotica Magazine |
| Dementia 13 | Infinite Edge | Proteus [1966] | The Vampire Journal |
| Descend | Infinity [1970] | Psychic Dimensions | Vanations |
| Destiny [1991] | Infinity [1987] | Pulsar! | The Velvet Vampyre |
| Dianoura | Infinity Ltd. | Purpleverse | Visionary Tongue |
| Diaspar | Inside (Science Fiction) | Quantum | Vortex Temporum |
| Diehard | Interstellar Fiction | Quantum Kiss | Waxen Wings and Banana Skins |
| A Different Path | InterText | Quantum Muse | Weird Space |
| Digital Catapult | In the Shadow of the Monolith | Radius | Whispers from the Dark |
| Digital Dragon | Invisible Stories | The Realm Beyond | White Dwarf |
| Digressions | Is | Realm of Fantasy | White Wolf |
| Dipple Chronicle | Ixxis | Redshift | The Wolverine |
| Distant Worlds | Jackhammer E-zine | Renaissance | Wotta World |
| Don-o-saur | Janus | Renard's Menagerie | Would That It Were |
| Doorways | Jayland Unlimited | ResAliens | Xeron |
| Double:Bill (fnz) | Jinnia Clan Journal | Residential Aliens | Yandro |
| Dragonlaugh | Jinx | Revolution Science Fiction | Yawning Vortex |
| Dragonlore | Kasma SF Magazine | The Richard S. Shaver Magazine | Ye Yowlings of Yog-Sothoth |
| Dragons, Knights and Angels | Kenoma | Rictus | Zenith (Speculation) |
| Dragonwings | Kinda Kinky | Rogue Worlds | The Zobee |
| The Dream Cell | Klein Bottle | Schlock! Webzine | |
| Dream Quest | Knights | Science*Fiction [1945] | |
| Dream Scene | The Kore | Science Fiction Scout |
Since the advent of the Internet, a number of websites have published original fiction online as individual short stories, sometimes on a regular basis and sometimes on a rather more "ad-hoc" basis. In the initial confusion between traditional "print" magazines and the newer "digital magazines" there was a regrettable tendency to classify anything published online as being a magazine and a number of "titles" crept into earlier views of the Science Fiction Index even though they couldn't conceivably be regarded as magazines. Rather than "lose" the data already entered, those already entered into the index will continue being listed as magazines until such time as the indexes provide alternative support for this sort of data, but have been moved to the Fictionmags Index for convenience. The "known" publishers affected by this are listed below (with hyperlinks to the entry in the Fictionmags Index where relevant).
| AE: The Canadian Science Fiction Review | Daily Science Fiction | Little Blue Marble | Sci Fiction |
| The Arcanist | Eclipse Online | Mad Scientist Journal | Strange Constellations |
| Black Gate Online | Enigmatic Electronic | Mysterion | Terraform |
| Cemetery Dance Online | Event Horizon (1998) | Persistent Visions | Tor.com |
| Cosmic Roots and Eldritch Shores | GigaNotoSaurus | Postscripts to Darkness |