9. Harpy Relic Silver Sword
Before the DLC packs came out, The Harpy Relic Silver Sword was the most powerful silver sword in the game.
So if you only own the base Witcher game, this rare find should absolutely be on your list.
While the requirements for wielding aren't exactly noob friendly, as it requires Geralt to be at least level 37, by the time you are able to wield it, Geralt will become a force to be reckoned with.
The diagram for the sword can be found one of two ways.
The first is during the main story quest: Wandering in the Dark. Without going too much into spoiler territory, the diagram can be found pretty easily inside the first room of the cave system that Geralt and his companion explore.
If you've already completed this quest, the diagram can also be found in a bandit camp east of the Red Baron's Keep.
Despite the fact that the sword needs to be crafted, the materials are surprisingly common and inexpensive for the game's best weapon, with the rarest item being one Ruby.
You'll also need some Dimeritium ingots and some monster saliva. What on earth you do with saliva when crafting a sword is a mystery, but hey, the results speak for themselves.