The Exodite Eldar warrior caste are known as Dragon Knights, after the various species of Dragons they ride into battle as mounts. These so-called 'Dragons,' mind you, are MOTHERFUCKING DINOSAURS! Think, Dino Riders in SPEHSS. Many of these different forms of dragons have greatly different forms, ranging from those that are the size of a horse, to much larger specimens the size of houses.
However, amongst these, only the more agile and smaller dragons are used for warfare. The leaders of the Dragon Knights are the Exodite Lords. They wield Laser Lances to complete the knightly look, just like the Shining Spear Aspect Warriors, because we haven't got enough knights in this game already.
On the Tabletop
As cool as their concept is, Dragon Knights haven't been a playable option since 2nd Edition, and even then they didn't have actual models, so if you wanted to field them, you were expected to kitbash your own out of Dark Elf Cold Ones. They also only had rules for one type of Horse-sized Dragon, so you couldn't bring anything bigger, denying you the chance to reenact Jurassic Park IN SPESS.
A single Dragon Knights squad could be between two and five warriors strong, each armed with a Laser Lance and Mesh Armour for a t-shirt save by default, for 36 points each without additional gear. They could also be upgraded with either Lasguns or Shuriken Catapults, as well as take their pick from the Assault Weapons list, giving them access to Chainswords, Laspistols, Power Axes, Power Fists, Power Swords, Hand Flamers, Needle Pistols, and Shuriken Pistols. This may seem pretty nifty now, but back then, your basic Guardians squad could do the exact same thing, and they even otherwise had the same profile as Guardians too.
Most of their cost went into their Laser Lances and mounts, which had M8, S/T4, and the Cause Fear and Cavalry Special Rules. The T4 didn't really matter though, as attacks against Cavalry used the rider's Toughness, in this case just T3, but they did get a +3 Armour Save bonus, better even that Ork Boarboyz with their fabled +2 (every other Cavalry only had a +1 at the time because they wussed out and rode Horses).