Sometimes Western and Eastern zodiacs and the Druidic Tree Birth Signs just don't cut it. Inventing new zodiac and horoscope systems is a nice way to add depth to a world different from ours, and a completely new birth sign/horoscope system can be used to give a basis for foreign myths and superstitions.
Often they would be related to Constellations, an elemental system, Animal and Mythical Motifs or other themes. As the Western Zodiac as the basics of astrology fictional deviations would be used to inform character traits be connected to destiny. However it is just as likely that they are just parodying those concepts and not take them seriously. Regardless of which, 12 would be the most common number for the signs, as both Eastern and Western variants have themnote
- Lucky Star once had a segment about horoscope sushi.
- Played With in Pokémon with one of the Johto Journeys episodes. Specifically, The Fortune Hunters had an Pokémon Horoscope, as follows: Ash was a Bellsprout type, Brock was a Onix type, Misty was a Gyarados type, Jessie was a Eevee type and James was a Moltres type. James was hyped about his fortune until it turned out to be a scam by Butch and Cassidy, another set of Team Rocket members. Then it turns out there's a separate, legitimate copy of The Fortune Hunters.
- World Trigger seems to have his own horoscope system too.
- Fan-written supplemental material for the Ravenloft setting gives it a zodiac based on the symbolism of the Tarokka deck, a Tarot-Expy published for use in Ravenloft games.
- Thir13en Ghosts has the Black Zodiac corresponding to the thirteen ghosts needed to activate Basileus's Machine and open the Ocularis Infernum.
- German Science Fiction Parody Film (T)Raumschiff Surprise Periode 1 has Mr. Spuck, a Vulcanette, who claims to have brimstone butterfly as his sign. He uses this as a pick-up line, claiming to be a good match for a Virgo (Rock Fertig-Aus, another protagonist).
- In Discworld the Disc has its own version of the zodiac. It involves such signs as The Small Boring Group of Faint Stars and Khefin's Eye 1-4. There are also a few other oddities:
- Because of the way Great A'Tuin travels through space, the zodiac is constantly changing.
- Because of the peculiar path the Discworld's sun needs to take in order for the seasons to work, all the constellations are in the zodiac.
- Dave Barry's Guide to Marriage and/or Sex has an astrological table with an abnormal set of birth signs: Virgil (Jan. 15Feb. 13), Aquarium (Feb. 14Mar. 18), Neptune (Mar. 19), Leon (July 20July 3), Psoriasis (Labor Day), Bob L. Hockmunster, Jr. (June 6 at around 2:30), and Sneezy (Giants* 6Dodgers 3).
- The Tough Guide To Fantasy Land says that the Management of Fantasyland is free to keep making up more star signs and astrological events until the entire sky is filled with unlikely conjunctions.
- Cantata in Coral and Ivory has different constellations from earth. The world also has four moons, which all affect a person's horoscope.
- Eberron has the Dragonmarked Houses, With 12 Dragonmarked for each Houses. (Phiarlan and Thuranni both use the same Dragonmarked, The Mark of Shadow) and the 12 Moon.
- The anthropomorphic game Ironclaw has it's own zodiac set that includes six objects and six mythical creatures.
- Dragon magazine #340, which had an astrology theme, based several of its articles around a zodiac comprising twelve Dungeons & Dragons monsters.
- The Elder Scrolls
- The series has thirteen birthsigns that the player can choose during character creation for certain bonuses. Some offer passive stat increases while others allow for a special power to be used, typically once per day. In Morrowind and Oblivion player may choose one of the signs as his birthsign in beginning of the game, while in Skyrim player may find and activate one of the Standing Stones, representing each sign. The signs and their months are: Morning Star - The Ritual, Sun's Dawn - The Lover, First Seed - The Lord, Rain's Hand- The Mage, Second Seed - The Shadow, Midyear - The Steed, Sun's Height - The Apprentice, Last Seed - The Warrior, Heartfire - The Lady, Frostfall - The Tower, Sun's Dusk - The Atronach, Evening Star - The Thief, and 13th Sign - The Serpent.
- The Magna-Ge, aka "Star Orphans", are heavily associated with the series' constellations and birthsigns. The Magna-Ge are et'Ada ("original spirits") who, along with their "father" Magnus (the architect of Mundus, the mortal realm), fled Mundus part way through its creation after Magnus realized that creating it would severely weaken the et'Ada and forever bind them to the world. While fleeing to Aetherius, the realm of magic, they punctured holes between the realms now seen as the sun (Magnus) and the stars (Magna-Ge), through which magic and light flow into Mundus.
- Final Fantasy XIV has the Twelve. a pantheon of twelve gods that correspond to an element, a month and a certain type of era. Players can pick one of them for an elemental bonus but this is more for flavor purposes.
- Pokémon Black and White has introduced a fictional zodiac loosely based on the Western one. The mons incorporated into this are (in order of month) Sawsbuck (Capricorn), Simipour (Aquarius), Alomomola (Pisces), Whimsicott (Aires), Bouffalant (Taurus), Klink (Gemini), Crustle (Cancer), Braviary (Leo), Gothorita (Virgo), Scolipede (Scorpio) and Fraxure (Sagittarius).
- In Kingdom of Loathing, upon Ascending you choose one of nine "moon signs", three for each of the three main stats (Muscle, Mysticality, and Moxie). These moon signs not only give different bonuses, but unlock one of three non-combat zones (a non-hostile version of Degrassi Knoll, Little Canadia, or the Gnomish Gnomad Camp).
- The troll species in Homestuck was said to have 48 signs, but this was only briefly touched upon once.
- Kim Possible has "Animology", an color/animal type personality quiz that gets treated like horoscopes (in that some people consider it BS and other don't). There is also an emphasis on "Soul-Mates" (with certain combinations considered to be particularly compatible with others).
- The Winx Club official site has a fictional zodiac using mythical creatures such as Pegasus, Gryphon, Dragon and Triton.
- Gravity Falls has its own Zodiac centered on a picture of Bill Cipher. They represent traits or, y'know, what you happen to be wearing at the time. In the series finale the main characters try to gather all the people in the zodiac together to defeat Bill Cipher, but an argument breaking out between Grunkle Stan and his brother Stanford spoils the whole thing.
- Until it was revealed to be a spoof intended to highlight the gullibility of people who beleived in astrology, a 1977 book by James Vogh entitled Arachne Rising; The Thirteenth Sign of the Zodiac was taken to be a scholarly work revealing that there were, in fact, thirteen star signs. Arachne, the Spider, was there in plain view in between Virgo and Libra. The fact it had been supressed by the usual suspects did much to explain why astrology is subtly "out", why a lot of people note feel none of the standard twelve apply to them; why some people feel they belong with the next sign along, not the one they were apparentrly born into; and would fit perfectly with there being thirteen lunar months. The book was serialised by the Daily Mail and hailed as a world-altering revelation. People even contested the idea - arguing that while there were thirteen signs and one had indeed been supressed in antiquity, the missing thirteenth sign was in fact Opiuchus the Serpent and not a bloody spider at all. As arguments raged between the spider and serpent factions and more newspapers ran with the sensation, it was revealed that it was, in fact, a piece of inspired trolling, proving some things (trolling) are older than the Internet. As one review phrased it:
Arachne Rising, the meticulously documented log of James Vogh's strange journey through the uncharted regions of mythology, archaeology, history, and language, will come to be recognized as a seminal work in astrology by those whose enthusiasm for the esoteric does not blind them to the need for sound scholarship, painstaking research, and rigorous application of scientific method.