Act 1
Mad Monarch's Scepter - 1h mace - After killing 10 enemies, you release a Poison Nova that deals 1050–1400% weapon damage as Poison to enemies within 30 yards
Ring of Royal Grandeur - Reduces the number of items needed for set bonuses by 1 (to a minimum of 2)
Pauldrons of the Skeleton King - When receiving fatal damage, there is a chance that you are instead restored to 25% of maximum Life and cause nearby enemies to flee in fear
Golden Gorget of Leoric Amulet - After earning a massacre bonus, 4–6 Skeletons are summoned to fight by your side for 10 seconds
Sanguinary Vambraces bracers - Chance on being hit to deal 1000% of your Thorns damage to nearby enemies
Act 2
Cloak of Deception - DH cloak - Enemy missiles sometimes pass through you harmlessly
Illusionary Boots - you may move unhindered through enemies
Gloves of Worship - Shrine effects last for 10 minutes
covens criterion- You take 50-60% less damage from blocked attacks
Act 3
Burst of Wrath - 2h axe - Killing enemies and destroying objects has a chance to grant 20% of your maximum primary resource
Boots of Disregard - Gain 500 Life Regeneration per second for each second you stand still. This effect stacks up to 8 times
Pride's Fall helm - Your Resource costs are reduced by 30% after not taking damage for 5 seconds
Envious Blade dagger - Gain 100% Critical Hit Chance against enemies at full health
Insatiable Belt - Picking up a Health Globe increases your maximum Life by 5% for 15 seconds, stacking up to 5 times
Overwhelming Desire amulet- Chance on hit to charm the enemy. While charmed, the enemy takes 35% more damage
Act 4
All of the legendary items drop in Act 4 - If you want a specific legendary, I'd advise against farming act4 as the chance is diluted by all other possible legendary item drops.
Act 5
Death's Bargain pants - Gain an aura of death that deals 750-1000% of your Life per Second to enemies within 20 yards. You no longer regenerate Life
Soulsmasher 2h - When you kill an enemy, it explodes for 500% of your life per kill as damage to all enemies within 20 yards, you no longer benefit from your life per kill
Helltrapper - 7–10% chance on hit to summon a Spike Trap, Caltrops or Sentry
Salvation shield - Blocked attacks heal you and your allies for the amount blocked
Pandemonium Loop - Enemies slain while Feared die in a bloody explosion and cause other nearby enemies