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 [1996] |
| Bardic Runes | Fantasy Jackpot | Multiverse Magazine | Spearhead |
| The Barsoomian | Fantasy Times | Muse Fantastique | Spectra-Foundation SF & Fantasy Mag |
| Bar Trek | Fantazone | Muzzy | Spectra Magazine |
| Basement Stories | Fanvariety | Mystic Signals | Speculation |
| Beabohema | Farrago | Mythagoras | Speculative Fiction and Beyond |
| Betelgeuse | Fear and Trembling Magazine | Mythos | Speculon |
| Bête Noire | FemSpec | The NASFA Shuttle | The Specusphere |
| Bewildering Stories | Fiction Inferno | Nebula [1950] | SPGA Showcase |
| Beyond [1943] | Fifth Di... | Nebula [1970] | Staffs and Starships |
| Beyond the Moon | Flapperhouse | Necrography | The Stake |
| Bite Me Magazine | Flash Fantastic! | Necrophantasy | The Standing Stone |
| Black Flames | Flashing Swords | Neometropolis | Stardust [1960s] |
| Black Hole | Fogfire | Neverary | Starlight |
| The Black Lily | Foma | Neverworlds | Starlit Fantasy |
| Black Moon | Fools Motley Magazine | New Realm | Steampunk Tales |
| Black Oracle | Fortean Bureau | New Venture [1975] | Stellarite |
| Black Skull Magazine | Foundation | New Witchcraft | STFanatic |
| Blood from 'Stones | Foxfire | New Words | Stone Telling |
| Bloodlines | Franson's | Next Phase | Straitjacket |
| Bloodrake | Freedom Fiction Journal | Nexxus | Strange Aeons [1990s] |
| The Blue Lady | F(r)iction | Night Dreams | Strange Aeons [2010] |
| Bone Chilling Tales | FTL Science Fiction | The Nightmare Express | Strange Brew |
| Bone Marrow Review | Full Moon S.F. | Nightmares Quarterly | Strange, Weird and Wonderful Magazine |
| Brain Harvest | Fusion Fragment [2007] | Nightside | Strange Wonderland |
| Brillig | Future Focus | Night to Dawn | Strix |
| Bulletin of Terrestrial Fantascience Guild | Futurian War Digest | Night Views | The Stylus [1993] |
| Burroughs Bulletin | Futurismic | Nightworld | Styx |
| Byzarium | Garage Floor | Niteblade | Sumer Morn |
| Cabal Asylum | Gathering Darkness | The Nocturnal Lyric | Sun Spots |
| Cactus | Gauntlet! The Magazine of Heroic Tales | Nomad | Surprising Stories |
| Camber | genrEzone | Not at Night | The Sword Review |
| Canadian Fandom | Giallar | Nova [1941] | Swords and Sorcery Magazine |
| Canticles from Labowitz | Glutonlumps Chilling Tales | Nova [1972] | Symphonie's Gift |
| Catenary Tales | Goblin Fruit | Nova [1989] | Syzygy |
| Cats with Wings | Golana | Novae Terrae | Tabebuian |
| Cemetery Moon | Golden Atom | The Nucleus | Talers Tales |
| Censored | Golden Visions Magazine | Nuketown | Tales from Texas |
| Centauri | Goodwitch Stories | Nu Ormenel Collected | Tales of Blood and Roses |
| Challenger | Gothic Light | Odd Tales of Wonder Magazine | Tales of Horror and Damnation |
| Chanticleer | Granfalloon | Of Unicorns and Space Stations | Tales of the Episco Pals |
| Chaos Theory: Tales Askew | Graveyard Rendezvous | Ogre | Tales of the Grotesque and Arabesque |
| The Chigger Patch of Fandom | Grimoire [1993] | Old Bones | The Tale Spinner |
| Chimaeran Review | Grok | Omnifan | Tangent [1976] |
| Chronicle | The Grotesque [1940s] | Omni Online | Terraform |
| Ciln | Grue [1953] | The Oracle [1982] | Terror |
| Cinquefoil | Gryffon's Star | Orion Science Fiction | Terror Hunters Journal |
| Citadel | Grymalkin | The Orphic Chronicle | The Thing |
| The City Morgue | Gryphonwood | Ouroboros | Third Order |
| Clarges | Hands in the Dark | The Outlander | Thirteen Magazine |
| The Comet (fnz) | Harbinger [1975] | Outside | This Way Up |
| The Communicator | The Hardcore | Outsider | Tiamat |
| Concept Sci-fi E-zine | Harsh Reality | Pages [1988] | TiconderogaOnline |
| Cosmic Speculative Fiction | Haunted Journal | Pan Demos | Time Travel Tales |
| Coyote Wild | Heart Attack | Pantechnicon | Tiofart |
| Crabapple | Heliocentric Net | Papyrus [1999] | TLMA |
| Crifanac | Heliophobe | Paradox [1942] | Tomorrow Magazine [1970] |
| Cyberpulp Magazine | Heliotrope | Parageography | Toward Tomorrow |
| Cygni | Hocus | Parlour Papers | Tower of Light |
| The Cygnus Chronicler | Holier Than Thou | Pegasus Online | Trail of Indiscretion |
| The Daily Phantagraph | Horizons (fnz) | Peridot Books | Transmission |
| Damned Thing | Horrorfest | The Periodical Lungfish | Troat |
| Dark Energy | The Horror Fiction Review (fnz) | Phantasia | The Tryout |
| Dark Infinity | The Horror Zine | Phenomena | TSAT (Transformation Stories) |
| Dark Moon Rising | The H.P. Lovecraft Fanzine | Phile | Twilight Garden |
| Dark Muse | Hugin and Munin | Piffle | Twilight Times |
| Dark's Art Parlour | Hyphen [1952] | Planet Magazine | Twin Cities SF & Fantasy Magazine |
| Dark Side | Ibidem | Planet Relish | Twisted Dreams Magazine |
| Dark Star | Ibn Qirtaiba | Pluto | Ultraverse |
| Dark Tome | If! (fnz) | Polaris [1940] | Undinal Songs |
| Dark Visions | IFA Review | Polaris [1980] | Universe Pathways |
| Darwin's Evolutions | Illumen | Polluto | Usok |
| Daughters of Nyx | Imagination [1971] | Popular Music & Science-Fiction Journal | Usva International |
| Dead Letters | Imagination [1990s] | Pornographic Onion | Utopian |
| Deadspawn | Imaginative Fiction | Port Iris | Vamperotica Magazine |
| Demensions | Incredible | Procyon | The Vampire Journal |
| Dementia 13 | Infinite Edge | Proteus [1966] | Vanations |
| Descend | Infinity [1970] | Psychic Dimensions | The Velvet Vampyre |
| Destiny [1991] | Infinity [1987] | Pulsar! | Visionary Tongue |
| Dianoura | Infinity Ltd. | Purpleverse | Vortex Temporum |
| Diaspar | Inside (Science Fiction) | Quantum | Waxen Wings and Banana Skins |
| Diehard | Interstellar Fiction | Quantum Kiss | Weird Space |
| A Different Path | InterText | Quantum Muse | Whispers from the Dark |
| Digital Catapult | In the Shadow of the Monolith | Radius | White Dwarf |
| Digital Dragon | Invisible Stories | The Realm Beyond | White Wolf |
| Digressions | Is | Realm of Fantasy | The Wolverine |
| Dipple Chronicle | Ixxis | Redshift | Wotta World |
| Distant Worlds | Jackhammer E-zine | Renaissance | Would That It Were |
| Don-o-saur | Janus | Renard's Menagerie | Xeron |
| Doorways | Jayland Unlimited | ResAliens | Yandro |
| Double:Bill (fnz) | Jinnia Clan Journal | Residential Aliens | Yawning Vortex |
| Dragonlaugh | Jinx | Revolution Science Fiction | Ye Yowlings of Yog-Sothoth |
| Dragonlore | Kasma SF Magazine | The Richard S. Shaver Magazine | Zenith (Speculation) |
| Dragons, Knights and Angels | Kenoma | Rictus | The Zobee |
| Dragonwings | Kinda Kinky | Rogue Worlds | |
| 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/Reactor |
| Cosmic Roots and Eldritch Shores | GigaNotoSaurus | Postscripts to Darkness |