This is my second reworking of this, with the addition of Mage Blades. Requirements will probably need worked on
Training Knife: Damage 3, Speed 2.5
Copper Knife: Damage 6, Speed 2.5, Requirement Daggers 1
Wasp Stinger: Damage 8, Speed 2.5, +3 Agility, Requirement Daggers 1
Spectral Knife: Damage 10, Speed 2.5, +1 Drain Life, +3 Agility, Requirement: Daggers 1
Bronze Knife: Damage 12, Speed 2.6, Requirement: Daggers 1
Bone Dirk: Damage 14, Speed 2.6, +1 Mastery of Dark, +3 Intelligence, Requirements: Daggers 2
Wolf Fang: Damage 16, Speed 2.6, +5 Agility, Requirements: Daggers 2, 12 Agility
Serpents Fang: Damage 15, Speed 2.6, +1 Double Attack, +2 Agility, Requirement: Daggers 2 (Would have poison type effect if applicable instead of Double Attack)
Iron Dagger: Damage 16, Speed 2.7, Requirements: Daggers 2
Hunting Knife: Damage 18, Speed 2.7, +1 Precision Strike, +4 Strength, Requirements: Daggers 2, 16 Strength
Icy Dirk: Damage 14, Speed 2.7, +1 Chill, Daggers 2
Steel Dagger: 24 Damage, 2.8 Speed, Requirements Daggers 3
Sharpened Steel Dagger: 28 Damage, 2.8 Speed, +1 Critical Hit, Requirements Daggers 3
Infernal Knife: 16 Damage, 2.8 Speed, +1 Fireball, Requirements Daggers 2
Demonic Blade: 24 Damage, 2.9 Speed, +1 Explosion, Requirements Daggers 3, 30 Intelligence, 25 Wisdom
Frenzied Dagger: 32 Damage, 2.9 Speed, +1 Rage, -3 Wisdom, +4 Agility, Requirements Daggers 3, 25 Strength
Bloodcursed Dagger: 40 Damage, 3 Speed, -2% MeleeAbs, -10 Toughness, +1 Critical Hit, Requirements Daggers 3
Black Dagger: 38 Damage, 3 Speed, +1 Daggers, +5 Strength, +4 Agility, Requirements Daggers 3, 30 Strength.
This is just a rough draft still, been doing some mock builds using this and current armor. even with an Agi build the Black Dagger at Level 30 can only get to 2.8s Speed, and if I'm right on Damage it should be around 139 (Maven would know better).
Edit: Changed Black Dagger, and Frenzied Dagger.