Caledor the Dragontamer
As his current status has always been "Unavailable for your shit", he has never had a model nor been featured in any artwork (although oftentimes fans will mistakenly ascribe artwork of his descendants Caledor I, Caledor II, or Prince Imrik to him).
Long ago, before Chaos came to the world, Caledor was a powerful Wizard who came from a southwestern kingdom known both for his friendship with the intelligent Dragons of Ulthuan and for his friendship with the great explorer Aenarion.
After Chaos came to the world, he fought against them although his forces were pushed back. Aenarion finally turned the battles against Chaos when he received a power boost from walking through Asuyan's sacrificial pyre, and the two managed to push the might of Chaos back across the land while pushing for more Elves to place their loyalty in Aenarion as the first king of the land. After the death of the Everqueen and Aenarion drawing the Widowmaker in grief, which Caledor desperately pleaded for him not to do, he could only watch as Aenarion went on a massive killing-spree against Chaos until falling in love with a young sorceress named Morathi. Caledor mistrusted Morathi, and (prior to a 7th edition retcon) suspected her of Chaos worship, but Aenarion had quite made a habit by that point of ignoring everything Caledor had to say.
Aenarion relocated his court to Morathi's homeland of Nagarythe, and rested on his laurels enjoying increasingly dark and wicked pleasures as Chaos destroyed the world in a full-scale invasion. Without alternative, Caledor came up with a plan to create a sink that would pull the magic Daemons use to manifest out of the world as fast as it rushed in through their Warp Gates and shoot it back into the Warp using a very complex ritual maintained by himself and other Wizards who would exist outside both sides of reality in a timeless island. Aenarion gave no fucks about Chaos anymore as snuff orgies had become more his and Morathi's thing, so he gathered Aenarion's forces and set out to do it himself.
Aenarion became enraged, initially coming to the island to kill him for his treachery although upon seeing the massive army of Daemons that had gathered to stop the plan, he helped instead. The spell succeeded, and the circle of Wizards with their master was cast outside of time creating a Vortex that saved the world.
Here, Caledor existed timelessly and was able to view both the Warp and the material plane, even beyond it, without limitation.
He was revered as one of the greatest heroes of all time, and the nation of Caledor where he originated from took its name from him (what it was called before is unknown). Two later Phoenix Kings, and most likely many Elves in general, also had this as their name.
Many years later (in a retconned Black Library book series called Defenders of Ulthuan/Sons of Ellyrion) Morathi came to the Vortex to kill him and the Wizards to bring Slaanesh directly into the world. She managed to stab a Wizard to death before he appeared in front of her as a mummy of an Elf, mocking her and saying how she was an idiot girl before and in thousands of years nothing had changed. She attempted to attack him before his form shifted back into the state of the prime of his life, and by sharing only some of his knowledge of the truth of reality with her he managed to burn both her soul and mind with searing red hot knowledge (basically the end of Indiana Jones: Temple of the Crystal Skull, but instead of turning to ash she simply pissed herself and ran away screaming). The descendant of the Wizard who had died, who had pursued Morathi, took the Wizard's place along with her fiance.
During End Times, Morathi attempted to stop Teclis from undoing the Vortex (quite a reversal) during his plan to attempt to stop Chaos by turning the Winds of Magic into power boosts for friendly individuals, and she failed. After mocking her during the scuffle, Caledor was left holding the screaming Morathi as both were pulled into the Warp by Slaanesh's waiting hand.
Although Morathi managed to survive into Age of Sigmar, Caledor the Dragontamer has been forgotten (although as all Elves Slaanesh had eaten were returned as mortal Aelfs he may have come back as well).