- Players in the card game Chrononauts each represent a character from a different timeline altering crucial events in modern history in an attempt to set things back to what his or her own present. One character is a sentient cockroach whose presence requires starting World War III.
- Psionics: The Next Stage in Human Evolution takes place in a universe where Project MK Ultra was successful.
- Alternate histories are a key element of the Feng Shui Tabletop RPG, with old timelines being erased and new ones being created as various factions gain or lose power in a conflict known as the Secret War. Most people don't notice when history changes, because their own histories have been rewritten to conform to the timeline alterations as well. However, Secret Warriors who have been to The Netherworld, an alternate dimension that facilitates Time Travel, retain memories of their former lives when these changes, known as "Critical Shifts," take place.
- The entire premise of the GURPS: Infinite Worlds campaign is based on one version of Earth (ours, known as "Homeline") discovering the means of traveling to hundreds of other alternate dimensions as reliably and economically as domestic air-travel is today, and engaging in a trans-dimensional cold war with a different version of Earth ("Centrum") with similar technology. Homeline's biggest concern is never, ever letting any other worlds figure out that travel between parallel universes is possible (let alone how to do it). Steve Jackson Games published two sourcebooks for the 3rd edition of the game, which detailed at least ten distinct worlds and offered seeds for dozens of variations.
- The tabletop and video game Crimson Skies exists in an alternate history where the United States broke up during the Depression and zeppelins actually succeeded as a transport product.
- The Tabletop RPG Traveller originally came out in the mid 1970s. The rather optimistic timeline of its official background universe, in which antigravity was invented in the 1980s and FTL travel in the 1990s, quickly became alternate history (and now seems to be officially accepted as AH, instead of trying to retcon it away).
- Similar to the above, Battletech's timeline originally began with the fall of the Soviet Union in 2011. After several messy attempts to retcon it to the Russian Federation or a re-established USSR, the writers have just declared it official AH as well.
- Timemaster. Members of the Time Corps (based in AD 7192 Earth) try to prevent their opponents, an alien race called the Demoreans, from changing human history to make it more to their liking.
- Deadlands starts by asking, "What if things that went bump in the night appeared in the middle of the American Civil War?" Their answer? Said war drags on for a decade longer than it "should," human technology springs forward in leaps and fits, and humanity potentially winds up dropping supernatural nuclear weaponry on itself. Better than it sounds.
- When Shadowrun originally began in the late '80s it wasn't alternate history. But since it passed 1999 when a Supreme Court decision gave corporations the right to their own militaries and 2001 when they gained extraterritoriality, effectively making them independent nations, it's become this. Nor did a dragon appear over Mount Fuji in 2011.
- Aces & Eights has a very in-depth alternate reality, just so players can't go about hunting down political figures just to say that they changed history.
- Gear Krieg, a table-top game determined to answer the age old question "What would the world be like if Hitler had had a jetpack?"
- Continuum is broadly about the players time-traveling to prevent this trope from occurring, since at best it usually has the effect of wiping out numerous time-travelers further Up the timeline.
- Microscope: a World Building game in which this is a definite possibility when players don't want to create a completely new Constructed World.
- In Rocket Age Rocket travel becomes a reality in 1931. As such, humanity expands out into the solar system.
- Through The Ages: Emphasised by the use of real-world names for wonders and leaders. Gandhi as president over a nation of scientists kept happy by Bread and Circuses? Isaac Newton builds the Taj Mahal and discovers computers? Elvis Presley conducts espionage, declares Holy War and builds the Kremlin? All are plausible occurrences and add significant amusement to the game.
- Alternate histories are an uncommon but canonical aspect of the more "cosmological horror" branches of the Chronicles Of Darkness, predominantly Mage: The Awakening and Demon: The Descent.
- One of the more infamous is the Prince of 100,000 Leaves from Mage: The Awakening: an alternate reality so horrible, so evil, that reality itself rejected it, flinging it into the Abyss, where it became sentient. It now tries to supplant "our" reality through the actions of the depraved Cult of the Red Word, who believe they can slowly overwrite reality with that of the 100,000 Leaves through ritual acts of cannibalism. How bad is this alternate history? In the 100,000 Leaves, cannibalism is a sacrament, disgust is love and abuse is kindness. Britain is known as the Theocracy of Vah and has a sadistic legal code, whilst the North American Continent is known as Chaannys, the Land of the Broken Turtleshell, whose princes impale the dead on bronze pikes so that their eyes can scan the living for signs of treason.
- Like Shadowrun, Cyberpunk 2020 has become this, with later editions of the sourcebook describing the game's timeline as an alternate one in which among other things the Soviet Union still exists into the 21st Century, cyberware -with its issues- and bioware are both ubiquitous and highly developed, corporations are almost de facto states with even standing armies, and despite having no smartphones or tablets and computers of specs ludicrously low next to real-world ones true Virtual Reality.
Alternate History / Tabletop Games