Horizon

Horizon is a line of five RPGs from Fantasy Flight Games that make use of the D20/Dungeons & Dragons 3.5 edition PHB and DMG to play. In essence, each is a short "campaign gazetteer" covering the bare minimum of fluff and the necessary special rules to play in the setting although how minimum that fluff is depends on the setting; Grimm, Virtual and Mechamorphosis all have pretty beefy lore segments, all things considered, whilst Redline and Spellslinger are quite minimalistic. Rare and obscure, you can probably torrent 'em if you go looking hard enough.

Grimm

Second of the Horizon lines, and the only one to get fleshed out into its own fully fledged game, Grimm is a Dark Fantasy game in which players take the role of kids exploring a magical world based on fairy tales that have gone hideously wrong. Like, "Rapunzel returned to her sapient tower, which killed her and uses her spider-infested corpse to lure children to their death" wrong. Your party takes the role of kids exploring this land of mad fey, evil witches, sapient (and hostile) terrain and raving lunacy, all under the guise of the mad lich-like creature known as King Humpty-Dumpty.

The core of Grimm's concept is that you play as human children, and thus race and class are instead replaced by a new system called Archetypes, allowing to play "standard" kid roles.

• The Bully is the muscle of the team, the tough and nasty one who now finds himself (or herself: girls can be bullies too!) in the role of protector against even worse creatures.
• The Dreamer was always lost in their own imagination before stumbling into the Grimm Lands, and that actually makes them better at surviving in this world of fae logic and mysticism than their more "grounded" counterparts, as they can intuitively grasp the fluid nature of reality.
• The Jock is a sports freak, but that's actually more useful than you'd think; they generally excel at working as a team, and they can keep up with the Bully in terms of brawn. Unfortunately, their focus on the physical makes them the worst at grasping the mystical aspects of reality here.
• The Nerd was the smart one, but it came at the cost of being physically and socially handicapped. Still, those brains come in handy.
• The Normal Kid is the jack of all trades, and the master of none. Still, by the faerie tale laws on which the Grimm Lands run, nobody can be that normal...
• The Outcast was the loner, the freak, the rejected one. Bitter, scarred and angry, their insistence on going their own way in real life actually makes them quite adapt at survival in the Grimm Lands.
• The Popular Kid is the social butterfly of the group, a natural leader and adept at manipulating those around them - enemy and ally alike.

Unique mechanics of Grimm include a Sanity analogue called Despair and expanded mechanics for the Swallow Whole system.

Mechamorphosis

The fifth and final in the Horizon line, Mechamorphosis is... well, it's Transformers with the serial numbers filed off. Do you really need to know any more? The rules are convoluted, but the default fluff actually is kind of nifty. Of course, we all know you'd rather run a straight up Transformers D20 game than use it.

For the curious, the basic fluff is that on the artificial world of Mecha Terra, a race of shapeshifting robots came to be. The lore on their origins has been largely covered up by the current ruling faction, the aptly-named "Tyrants", whose official party line is that the mechamorphs sprang into being from the Great Generator that lies at the heart of Mecha Terra. Whispers exist of other possibilities, mostly centering on alien creators who either died out or left. For an untold age, Mecha Terra was divided between an array of mechamorph guilds that controlled singular aspects of society, such as construction research and commerce. The guild leaders collectively governed Mecha Terra in an assembly known as the Cynet. It was a paradisical age as the mechamorphs converted the once-organic world into a mighty ecumenopolis, then spread to other colony worlds... that all came to an end when the Great Generator stopped providing power. Mecha Terra was on the verge of civil war, until a new guild arose: the Tyrants. Led by the charismatic Obelisk, they promised to share vast supplies of energy if the Cynet stepped down, and to their credit, the planet's former leaders did.

The Tyrants quickly and mercilessly consolidated their power, then began launching a series of expeditions into the stars in hopes of finding new worlds to draw natural resources from. Although some succeeded, many perished in deep space, but the Tyrants continued to launch their expeditions. With a stranglehold over the supply of energy, they quickly set themselves up as the benevolent overlords of Mecha Terra.

...Of course, it was all a complete farce. Pride, guild leader of the Animechs - a mechamorph guild that animated and rebuilt destroyed mechamorphs - discovered the dark secret of the Tyrants: the so-called "Explorers" were not perishing in the darkness of space, but were actually being murdered by the Tyrants, who were cannibalizing their supplies of precious nexus energy to feed the rest of Mecha Terra. When the Animechs confronted Obelisk, however, they were faced with the possibility of a terrible civil war: unwilling to take that risk, Pride led his guild to flee Mecha Terra, only for Obelisk to lead an attack on the Animechs ship, which led to their seemingly mutual destruction.

Tens of thousands of years passed as the Tyrants openly and brutally oppressed their followers, grinding them down with ever-stricter rationing and launching brutal campaigns of plunder and conquest on the wider galaxy. Eventually, the non-Tyrants reached their breaking point; under the leadership of a mechamorph named Aegis, nine former guild leaders came together and founded the Exiles, those who would flee Mecha Terra from their murderous masters.

To do so, they dared the impossible and penetrated a nearby spatial anomaly called "the white hole", a rift in space that sent them to Earth. Followed by an ambitious and high-ranking Tyrant named Vorpal, Aegis and his followers now battle for their survival on the alien world... which may also be the final resting place of the dread nexus siphon technology originally used by Obelisk to found the Tyrants in the first place.

The mechamorph race is one of the most in-depth pieces of this line; creating your own mechamorph requires two chapters - one to cover the basic racial traits and how to adjust strength and scale when dealing with giant robots, and then a second chapter all about designing your alt-forms. A third, technically optional, chapter covers "special powers", which includes both spell-like abilities (which stand in for Transformer superpowers, like Skywarp's teleportation or Mirage's invisibility) as well as the ability to create Xmaster or gestalt style fused characters. Then a fourth chapter covers vehicle movement and combat.

For the curious, the basic racial traits of the mechamorph are:

Modular Design: A mechamorph has to choose the prioritization level of five character aspects at character creation; Alt Form Design, Form Feats, Ability Scores, Special Powers, and Gear. Priority ranks from 1 (Least Important) to 5 (Most Important). The higher the value, the better that aspect is.

Alt Form Design: The "potency" of your alt form. Examples are Dirt Bike (1), Tank (2), Fighter Jet (3), Laptop (4), Spaceship (5).

Form Feats: 2 per Priority rank.

Ability Scores: A mechamorph starts with an 8 in all stats and 20 ability score points to divide between them at Priority 1. Each priority rank grants +4 ability score points to assign.

Special Powers: 1 per Priority rank.

Gear: 2 per Priority rank.

Size: Unless the Massmorph special power is taken, a mechamorph's default form's Size Category must be within (Alt Form Design Priority Rank) steps of its alt form's Size Category (for example, a mechamorph with a Small alt form and Priority 1: Alt Form Design must have a Small or Medium primary form).

Living Machine: A mechamorph is immune to gases and poisons, doesn't need to breathe or eat, and is immune to death, nausea, paralysis, petrification and unconsciousness effects that specifically target organics - anti-machine effects that cause those conditions work fine. They are vulnerable to exhaustion, mind-affecting effects, and critical hits. A mechamorph is staggered at 0 HP, unconscious at -1 HP, and destroyed at -10 HP. A destroyed mechamorph can be brought back to life by using the Rebuild class feature, which requires a series of Build/Repair and Computer Use checks.

Fuel Dependant: A mechamorph must spend at least 4 hours each day in stasis (asleep) or suffer fatigue and eventually exhaustion.

Vital Systems: When a mechamorph suffers a critical hit, it needs to roll a d20 on the Mechamorph Critical Hits table to determine which system is damaged. Weapons with an "X(number)" critical trait cause multiple rolls on the table.

Damage Reduction: 10/Nexus Energy in all forms.

Energy Resistance: 10 (all energy types).

Vulnerable Circuitry: A mechamorph takes full damage from energy that bypasses its Energy Resistance, rather than the usual half/quarter damage of an object.

Imbued Attack: A mechamorph's unarmed strikes count as being made with Nexus Energy. However, a mechamorph's unarmed strikes only do non-lethal damage unless it has Improved Unarmed Strike or a natural weapon.

Rapid Healing: A mechamorph recovers 1 HP per hour and 1 ability damage per hour. Hit point recovery increases to (character level) points per hour when in stasis.

Nexus Energy Reserve: A mechamorph has a reserve of nexus energy points equal to their character level. Once per round as a free action, a mechamorph can tap nexus energy to empower themselves. They can either grant a luck bonus to an attack roll, saving throw, or their armor class (bonus equals nexus points spent), absorb damage equal to nexus points spent, or alleviate fatigue from avoiding stasis by spending (1/2 character level, rounded up) nexus points. All nexus points regenerate when a mechamorph completes their daily 4 hours in stasis. Mechamorphs can also "cannibalize" their vital energies if they lack sufficient nexus energy, suffering 1 temporary Constitution damage per "missing" point of nexus energy. To cure this damage, a mechamorph must endure a 4-hour long stasis period specifically to recover from the strain, which means it stacks with the daily 4 hours required.

Morph (Ex): A mechamorph has two forms, possibly more, and can move between forms as a move action that doesn't provoke attacks of opportunity. Mechamorphs with a BAB of +5 or more can morph as a free action after moving. If grappled, a mechamorph must pass a grapple check to morph first, and cannot morph if pinned. Unless the alt form is that of an animal, a mechamorph retains all abilities, base attack bonus, hit points, skills, feats, and sensory abilities in alt form. Mechamorphs can use special powers in alt form. All gear is either dropped or stowed in cargo (as appropriate) when the mechamorph enters alt form unless the gear has the Linked trait.

Level Adjustment: +6

Mechamorphs have access to four classes; the Controller (a minion-master in the vein of Soundwave or Blaster), the Scientist (focused on repairs, building stuff, gear and/or special powers), the Scout (the sneaky class) and the Soldier (the fighting class). Unlike standard D&D classes, all of these classes instead have trees of optional class abilities that the mechamorph can choose between as they level up, increasing character customization.

Redline

Redline was the first Horizon setting to be launched, and can be summed up as "2 parts Mad Max, 1 part Fallout". Created before d20 Apocalypse was a thing, Redline takes place in the post-apocalytic ruins of an Earth devastated by World War 3. Miraculously, despite the cataclysmic usage of atomic, biological and chemical weaponry, and the environmental devastation that plunged the known world into severe droughts, humanity has clung to existence. Now the survivors largely eke out a life as nomadic technobarbarian scavengers, using the lingering remnants of the highways and byways to traverse the ruined earth to forage for what supplies remain. Even those few permanent settlements maintain bands of road warriors who ride out into the wastes to retrieve vital goods from afar. And all the while, they strive to avoid the deadly touch of "The Creep" - the mutagenic toxins left behind by the apocalypse.

In lieu of races, Redline uses a set of six Backgrounds, which roughly correspond to popular archetypes from post-apocalyptic fiction. These give your otherwise all-human party a more unique mix of backstories, abilities and skills, with mechanical reinforcement to boot.

• Bornagains are defined by their deep religious faith, which makes them natural preachers, leaders and philosophers.
• Bygones are also defined by faith - but theirs is in the human capacity to rebuild and restore the civilization that once was, to life mankind out of the fires of barbarity and back to its former place of technological supremity.
• Drifters are lone wanderers, tough, hardy, self-reliant and determined to survive, no matter the odds.
• Ferals have regressed even deeper into barbarity than is normal for the world of Redline, becoming at best neo-tribals and at worst little more than animals that walk on two legs.
• Rejects are born mutants, stronger and tougher than humans, and able to ignore the caress of the Creep, but duller-witted and plagued by random biological defects.
• Savants are scramble-brains who have uncanny intelligence and focus on select topic of interests, but otherwise are seriously handicapped in looking after themselves.

Like all Horizon settings, Redline uses its own set of unique classes; the melee-focused Marauder, the guns-and-driving-focused Redliner, the tech-scavening and repairing Rigger, the charismatic Trader, and the Walker, a hardy survivor willing to brave the wastes on foot and with the aid of a loyal bestial companion.

Unique mechanics from Redline consist of vehicular combat, the Creep, and Creep mutations.

Spellslinger

The fourth of the Horizon line, Spellslinger is a distinctive and unique blend of traditional D&D and Weird Western, taking the traditional D&D races and putting them in a knock-off Wild West setting. No 9 level spellcasters here; you get a select few spell-like abilities via the Brands system, and you can't multiclass 'em. On the awesome side, it includes pretty decent D20 rules for Western-grade guns and the fluff is actually pretty cool. Oh, and it's got a race of carnivorous killer horse-things as new mounts. On the downside, there's only one new race, and that's anthro wolf totally-not-American-Indians called the Gray Runners, who sort of rip-off the Lupins.

This one's in-detail enough that we put it on its own page, over on Spellslinger.

Virtual

The third in the Horizon series, Virtual can be summed up quickly and simply as "Tron d20" (or perhaps Reboot d20). For those of you who don't know what Tron is, Virtual is set inside an artificial world that exists within the collective software of the internet, known as "Program Space". In Program Space, players take the role of the sapient programs that have been spawned as an accidental byproduct of the great and terrible super computer-viruses that have been waging war over the very substrata of Program Space since its founding. Their goal is simple: survival in the face of an alien, hostile world.

Programs are divided into three categories; non-sapient Sleepers, fledgling sapient Dreamers, and fully sapient Wakers. Wakers themselves are divided into three major factions; System Programs (continuing to serve the function they were originally created for), Rogue Programs (stubbornly independent in the face of Users and super viruses alike), and Razors (Wakers who choose to serve the viruses that gave them sapience). Players take the role of Wakers, obviously.

The "race" system of Virtual is divided into two halves; Heritage and Form.

'Heritages represent the original viral strain that a Program descends from, and provide ability score modifiers as well as a small number of racial traits. The available Heritages are Absorber (descended from morphic viruses), Controller (progeny of boot viruses), Destroyer (from destructive viruses), Hider (from stealth viruses), Infecter (from program viruses) and Resisters (created by viruses characterized by tenacity).

Form represents the specific bodily structure that a Program asigns to itself as it matures from its original state as a being of pure data into a "coherent" denizen of Program Space. The most common are Userclones, who take on a basic humanoid form. Bantams are small, lithe and stealthy, and can be anything from small demihumans like fairies, dwarves or imps to Userclone children. Titans, in contrast, are big, powerful, hulking figures fitting of the name. Primals reject a humanoid form entirely and style themselves after either a bird or a predatory beast. Finally, Prototypes defy simple description, being the most "state of the art" forms.

For classes, Virtual relies on its own six signature classes:

• The Antiviral is a unarmed warrior-medic able to heal and harm with its very touch.
• The Battle AI is basically a fighter, being the master of combat.
• The Messenger specialises in traveling far and wide at great speed, and serves as the Virtual rogue.
• The Programmer specializes in rewriting Program Space itself, essentially the wizard of the cyberspace plane.
• The Thinker is a unique combination of a Skill Monkey and a Half Caster.
• The Webcrawler is a strange hybrid of ranger and assassin, with an ability to track down anything.