The Witcher steel swords

In The Witcher, steel swords are used primarily against humans, and nonhumans, as they reportedly have little effect on monsters.

Witcher's Steel Blade
The Witcher's Steel Blade is one of the steel swords that Geralt receives at the beginning of the game, during the prologue (the very first being a rusty sword). Alhough it is used primarily against humans and has little effect on monsters, Geralt is able to fight off most monsters during the early stages of the game using only this sword.

Ceremonial Sword of Deithwen
This sword can be found several places, like some blacksmith shops, usually after Act III.

D'yaebl
This sword is given to Geralt by Velerad as a gift from King Foltest for curing Princess Adda.

Elven Sword of the Blue Mountains
This sword is carried by elves and so is not usually found anywhere but in their remains.

G'valchir
This is the sword, a Mahakaman rune sihill, Geralt receives from the dentist for completing the Won't Hurt a Bit quest. It can also be obtained by completing Mud and Velvet quest by keeping the money for yourself (if so, you have to kill Captain Jean-Pierre).

Gwalhir
This sword can be bought from blacksmith's son during Act IV. I have not found it in any remains, but it is better than Harvall.

Harvall
Harvall can be found in Act II, or III in the swamp on a decomposing body on Wyvern Island (in the north central part of the Swamp). It is a much better blade that the default witcher's steel blade, so if you get it in Act II, keep it and sell the witcher's steel blade instead.

Holy Sword of the Order
This sword can be found on on the body of Patrick de Weyze after a battle during one path of an Act III sidequest.

Illegal Sword
These swords can be found on the corpses of vanquished Salamandra anywhere from Act III onward.

Rusty Sword
Rusty swords can be found in lots of remains of adversaries, but sometimes in containers, most commonly in the early Acts.

Sword of the Order
This sword can be found on guards affiliated with the Order of the Flaming Rose, anywhere from Act II onward.

Temerian Steel Sword
These swords are sold most everywhere and are also found on many bodies throughout the game.