Horselord

The Horselord is a Barbarian Variant Class from Dungeons & Dragons 3rd Edition that debuted in Dragon Magazine #338. It's basically a mounted barbariant variant, inspired by the Mongols and to a lesser extent by the horseriding warriors of the Native American tribes from classic Westerns. Mechanically, horselords are identical to standard barbarians, except as follows:

• They lose the Fast Movement and Trap Sense abilities.
• They gain the Expert Rider ability; they suffer no penalties to Ride checks for riding bareback and gain a +2 bonus to Ride checks when using a saddle. They also gain Mount Familiarity, which gives them a +2 bonus to Handle Animal checks with a single species of rideable animal - this is most conventionally a horse, but could be anything your setting allows to be ridden, even weird fantasy steeds like chocobos and dinosaurs.
• They replace Rage with Battle Ecstasy, which functions largely the same; when a horselord enters Battle Ecstasy, they gain +4 Dexterity, +4 Constitution, and Damage Reduction as per Rage. A horselord can use any skill or feat whilst in Battle Ecstasy, but suffers a -2 penalty to all of them except for Handle Animal and Ride. Battle Ecstasy lasts as long as Rage and fatigues the horselord just like a rage, until they reach 17th level when the fatigue penalty vanishes. There is no Greater Rage or Mighty Rage equivalent for Battle Ecstasy.
• At 4th level, they gain Faithful Steed; essentially, after spending 2 months owning and riding a specific mount, the horselord can turn that mount into an Animal Companion, which functions identically to the animal companion of a ranger of the same level, except that its type remains Animal, not Magical Beast. Replacing a slain Faithful Steed requires 1d4 months of searching and a successful DC 15 Handle Animal check.
• Finally, at 6th level, the Horselord gains Improved Mounted Archery as a bonus feat.