Horse

Horses are creatures mentioned before and after the Great War.

Background
References to the animals can be found in dialogue and on related world objects.

Fallout

 * Dane, one of the Children of the Cathedral, will mention horses in his ramblings.

Fallout 2

 * When talking to Ethyl Wright, the Chosen One may mention enjoying fermented milk from a mare, or female horse.
 * Lenny may exclaim, "I've got to talk to a man about a horse" before running away from combat.

Fallout 3

 * A horse toy called the Giddyup Buttercup was popular before the war. Advertisements describe the toy as, "perfectly emulating the behavior of an actual horse."

Fallout: New Vegas

 * Swank refers to New Vegas as a "wild horse" when the Courier asks for his thoughts on Robert House.
 * A book entitled Pretty Pretty Horsies: A History of the Mongol Empire is a quest item used to convince the Great Khans to break their alliance with Caesar's Legion, by revealing the history of their namesake ancestors.
 * There is a horse toy shown on the Big Ranch Nevada State Lotto billboard in the Mojave Wasteland.
 * Arcade Gannon refers to those preparing for the Second Battle of Hoover Dam as "warhorses."
 * In Honest Hearts, the war clubs used by the Dead Horses have been carved into the shape of a horse head.
 * Festus offers the Courier an opportunity to play a game called Lucky Horseshoes.
 * On the cover of Tæles of Chivalrie, a knight can be seen riding a horse whilst fighting a dragon.

Fallout 4

 * There is a drawing of a horse, chicken and cow used in a framed picture near Bunker Hill. The same drawing appears at an unmarked trapper outpost northwest of the MS Azalea, in the add-on Far Harbor.
 * Napoleon's ceremonial parades on horseback throughout Europe are mentioned on a plaque in the Wixon's Shovel Museum.
 * A horse is part of the Paul Revere Monument in Boston.
 * The Easy City Downs‎‎ Racetrack and Clubhouse featured horse races before the war, and horses are depicted on its signage.
 * Members of the Pack ask one another what a horse was, and if it was similar to a large dog that one could ride.
 * Porter Gage mentions horses twice, once in a reference to betting and once telling the Sole Survivor to "have fun getting shot from off the top of your high horse."
 * The Giddyup Kid asks for help corralling horses. If dressed as the Silver Shroud, the Sole Survivor can agree to help, stating, "Horses gone missing? The Silver Shroud shall ensure this is not part of some more diabolical plot." If successful, Giddyup Kid, Sheriff Hawk, and Sheriff Eagle will express their gratitude.
 * Nick Valentine uses the phrase "hold your horses" several times.
 * Cait mentions that she is not one to "look a gift horse in the mouth."
 * If the Sole Survivor helps Far Harbor's Cassie Dalton avenge her family, she will comment about a horse and riding off into the sunset.

Fallout 76

 * There is a horse on the sign for the Flatwoods Tavern.
 * Story Time Miss Nanny mentions horses during the story "Cinderella" that she will tell to the Vault Dweller as part of a random encounter.
 * Horse trailers are found on roadways and in barns around Appalachia.
 * Thurston Wellingham mentions a fully-staffed horse riding stable available to children at Bolton Greens.
 * Several different varieties of horses serve as part of the carousel ride at Camden Park.
 * Horseshoes are mentioned in the Prickett's Fort audio tour.
 * Scout Leader Jaggy laments about missing the sight of horses in Appalachia.
 * In Berkeley Springs Station, the wallpaper is patterned with pictures of horses.
 * A location in Appalachia is named Horse Creek Petroglyphs.