In Harry potter and the Cursed Child, people in alternate reality say "For Voldemort and Valor". What is "Valor"?
There is a graveyard named Valor but it seems irrelevant.
In this case, "valor" simply has its common meaning of "bravery." I would guess that "valor" was chosen since it starts with the same letter as "Voldemort," making for a nice alliterative motto. One might note some similarities with a certain alliterative greeting used by real-life supremacist groups.
It also recalls the slogan "Magic is Might," used by the Voldemort-controlled Ministry in Deathly Hallows.
The great Atrium seemed darker than Harry remembered it. Previously a golden fountain had filled the center of the hall, casting shimmering spots of light over the polished wooden floor and walls. Now a gigantic statue of black stone dominated the scene. It was rather frightening, this was sculpture of a witch and a wizard sitting on ornately carved thrones, looking down at the Ministry workers toppling out of fireplaces below them. Engraved in foot-high letters at the base of the statue were the words MAGIC IS MIGHT.
—Harry Potter and the Deathly Hallows
I cannot recall any mention of the word Valor as a place or character name in Harry Potter, so I doubt it has any further significance.