When building a fantasy world, you draw inspiration from the real world for some of the practical details. In "Game of Thrones" (or "A Song of Ice and Fire" to my fellow book readers), almost every tool of death is based off of an actual weapon.
Excluding mythical things, like the Night King's ice spear or Daenerys' dragons (which are totally A-10s), you can usually point to a real weapon that bares a striking resemblance to the one in the series.
Jon Snow's sword isn't unique... at all.
Of course, Non-Valerian steel swords like Jon Snow's exist, and having animal designs on the pommel are nothing new, but the devil is in the details of pinpointing specifically where they originate.
Everyone from the Vikings to Filipino warriors to the Romans made cool designs on the pommel. Those are cool and all, but do they open their eyes? Probably not. And neither did Jon's.
The Mountain's sword is an Irish Long Sword
The Mountain, being the strongest man in Westeros and the strongest man on Earth, would need an equally powerful weapon. What stands out about Gregor Clegane's weapon is the pommel. It's a symbol common among Irish long swords. It's also featured prominently in the show as well in Sansa's necklace as well as Cersei. Just throwing that out there...
Arya's Needle is a French Rapier
Jon had a tiny sword made for Arya long before she turned into a faceless assassin who knew how to use it. Her blade doesn't have an edge and is best "sticking them with the pointy end."
It's a lot like an actual rapier used as a Main-gauche, or parrying dagger used with the off hand.
Dothraki Arakh is the Egyptian Khopesh
The weapon of choice for the Dothraki and Daario come from the Egyptian sickle-sword. The advantage of using a khopesh is that it serves several purposes. It's great as a sword, good as an ax, and excellent as a hook.
Wildfire is Greek Fire
The Wildfire used by the Lannisters is devastating. It won the Battle of Blackwater Bay and blew up the Septum. An extremely early version of a napalm thrower was used by the Byzantines for naval combat as early as 672.
Lannister's Scorpion is the Roman Scorpion
Give it up for my boy Bronn. Sure, there may be heroic battles and perilous combat throughout the series. But to stare down a dragon with an untested weapon after it wrecked havoc on all of your fellow soldiers... Balls of Valerian f*cking Steel.
In real life, Greeks and eventually Romans used a smaller version that was perfect for long range combat.
Benjen Stark (Cold Hands)'s flail is a burning version of a Japanese Chain Weapon
Most depictions of flails in popular culture are actually debatable for being historically accurate. If they had a chain, it was short for close combat. If it was longer, it'd be two handed and used on horseback (like Benjen).
The closest to reality that Benjen uses is perhaps a variation of the kusarigama, a weapon synonymous with another historically debatable group: ninjas.
Tormund's Ax is a Mesoamerican Macuahuitl
This one blows my mind for not just its similarly primitive design, but also how it was made. It's never outright stated in the show, but it looks as if his ax is made of Dragonglass — something we know can kill White Walkers and Wights. Dragonglass is also known as obsidian in the show and lore.
In early Mesoamerica, warriors would use chipped obsidian on sticks to create a devastating sword/ax that could cut through their foes.
Beric's flaming sword is a circus performer's sword... and, uh, this guy's sword...
Beric has these guys beat by using magic to light their swords on fire, but it's been a common tactic used in lighting arrows on fire. A burning sword is cool, but impractical for actual fighting because it would need a constant supply of fuel.
This is why it's just used by circus performers.
But then again. A fan recreated the Shishkebab from Fallout 4, giving it a constant source of fire. So this guy beat him to it.
For more insight into the practicality of the "Game of Thrones" weapons, check out the link below: