Toxin Blade
The Toxin Blade temporarily blinds the enemy when they have been cut.
Location:
Upper Seattle, Emerald Suites, Apartment 2225.
In the bedroom under the Pillow.
Dragon Toothe Sword
Extra Damage
Location:
Antarctica, JC Denton's Fortress, JC Denton's mind pocket, Maggie Chow's Apartment.
At the apartment talk to the Gray and look on top of the bookcase.
Hellfire Boltcaster
They ignite when health gets low enough.
Location:
New Cairo (first visit), Medina, Nassif Greenhouse.
Extremely hard to get. Once you enter the Green house look up and you should see what looks like another apartment. Get to the area that overlooks the entrance then jump onto the little edge that on the other side of the guard rail. Then follow it to an area that is on an adjacent wall and jump onto the shut window and then jump once more but hold Y to mantle and climb over the rail. You will then find it in the junk.
Red Greasal Hunter
Bit stronger, red light as secondary fire.
Location:
Lower Seattle, Sewer.
By the dead Omar guarded by Karkians.

Assassin Pistol
Increased damage, increased range, bit slower rate of fire, scope as alternate.
Location:
Trier, Nine Worlds Tavern, Der Blutende Rabe Curio Shop.
Enter the room and go behind the Omar to the right corner andyou'll find it under some junk.
Widow Maker SMG
Slightly less recoil, launches Spiderbomb as secondary
Location:
New Cairo (Second visit), Arcology, Level 107, Maintenance Tunnel.
An open area where electricity is flashing. When you have entered it follow the path and you'll find a dead SSC Guard with it in the junk.