Why did Voldemort never seek the Hallows before the events of the second wizard war? It seems it would have been much easier for him to retrieve them. James had the cloak, Regulus had the resurrection stone(not sure if I remember that correctly, I could be wrong), and Dumbledore had the elder wand. It seems that it would have been much easier for Voldemort to get to the three seeing as the cloak was with Harry who's location was unknown and the stone was within the snitch Harry caught, which only he could open. So, why did Voldemort wait to seek the Hallows?
He'd never heard of them, very few wizards ever had, and fewer still would have believed they could exist.
Before the events of The Deathly Hallows, there were only 3 people we know in-canon who had heard of and believed in the existence of the Hallows: Gellert Grindelwald, Albus Dumbledore and Xenophilius Lovegood. The only text we're ever presented as evidence for their existence is a children's book; The Tales of Beedle the Bard, which Voldemort would never have read as he grew up in a Muggle orphanage.
Ollivander knew of the Elder Wand, and it's likely that Voldemort found out about it through him after Harry defeated Voldemort while he was using Lucius Malfoy's wand, but Ollivander has never heard of The Deathly Hallows (as he tells Harry in Shell Cottage), and so couldn't have told Voldemort about the existence of the other two. And even if somehow, some strange Death Eater who believed in children's stories told Voldemort about the Hallows, it wouldn't have mattered, as Dumbledore says:
But even if he had known about them, Harry. I doubt that he would have been interested in any except the first. He would not think that he needed the Cloak, and as for the stone, whom would he want to bring back from the dead? He fears the dead. He does not love.”
As Xenophilius Lovegood said in Chapter Twenty Two of The Deathly Hallows:
The bloody trail of the Elder Wand is splattered across the pages of wizarding history.
The Elder Wand wasn't known by Voldemort as one of the Three Hallows, as he wasn't aware of the fact that there were three. The Elder Wand gained notoriety on its own apart from the other Hallows which Voldemort would undoubtedly know from his dabbing in dark magic.