Melee Weapons in 40K

Chainsword: Damage 1d8, One Handed, Versatile, Rend (DC12 CON or +2d4 damage).  

Eviscerator: Damage 2d10, Two Handed, Heavy, Rend (DC12 CON or +4d4 damage), Deals double damage vs vehicles and buildings.

Power Sword: Damage 1d8, +1 to attack, One Handed, Versatile, Finesse, Power Cell - Ignores AC from Armor (Power or weaker).

Power Axe: Damage 1d12, -1 to attack, One Handed, Heavy, Power Cell - Ignores AC from Armor (Power or weaker).

Power Maul: Damage 1d8, One Handed, Heavy, Power Cell - Ignores AC from Armor (Power or weaker), Bash (DC12 CON or +1d4 damage).

Power Fist: Damage 3d8, - 2 to attack, One Handed, Heavy, Power Cell - Ignores AC from Armor (Terminator or weaker), Bash (DC12 CON or +4d4 damage).

Lightning Claw: Damage 2d6, One Handed, Versatile, Finesse, +2 to attack and +1d6 damage each if worn as pair, Ignores AC from Armor (Power or weaker).

Chainfist (Terminator Armor only): Damage 3d8, - 2 to attack, One Handed, Heavy, Power Cell - Ignores AC from Armor (Terminator or weaker), Bash (DC12 CON or +4d4 damage), Deals double damage vs vehicles and buildings (no penalty to attack).

Thunder Hammer: Damage 6d8, - 2 to attack, One Handed, Heavy, Power Cell - Ignores AC from Armor (Terminator or weaker).

Heavy Thunder Hammer: Damage 6d8, - 2 to attack, Two Handed, Heavy, Power Cell - Ignores AC from Armor (Terminator or weaker), Special*

* On a successful hit the opponent must succeed a DC12 CON save or have the attack be treated as a critical.

Sarissa: Damage 1d6, Versatile, Finesse, added to a Bolter.

Axe of the Omnissiah (Tech-Marine only): Damage 1d12, -1 to attack, Two Handed, Heavy, Power Cell - Ignores AC from Armor (Power or weaker), Special*

* Grants +1 bonus to all Mechanics rolls
* Deals double damage to vehicules and machinery

Crozius Arcanum (Chaplain only): Damage 1d8, +1 to attack, One Handed, Heavy, Power Cell - Ignores AC from Armor (Power or weaker), Bash (DC12 CON or +3d4 damage), adds proficiency bonus to damage.

Relic Blade: Damage 1d10, +1 to attack, One Handed, Versatile, Finesse, Power Cell - Ignores AC from Armor (Power or weaker), adds proficiency bonus to damage.