For most of these items, the ability you see would be per piece (so multiply all effects by four to get the result for wearing the set). There may be one or two expections.
1) -25% mana regen from spirit. Gain up to 40 mana every time a spell crits.
2) For each target that you have a moonfire on, they take 3% of your heal spells as damage.
1) -10% movement speed. Each ranged attack has a 5% chance of granting you 2 extra attacks with 170 extra attack power.
2) When pet crits it gains a +35 attack power and increases size. This buff lasts 10 seconds, and can stack up to five times.
1) -6% damage on non-crit spells. +6% damage on crits
2) Every time you cast arcane explosion you gain a shield that will prevent the next 25 damage.
1) Actually, I don't like this one. It was boring, so I'll come up with a new one later.
2) On healing spell crits you have a 2% chance to create a shield that will prevent all damage. The shield will last for one second.
1) Your spells have a 2% chance to fail when cast. You have a 3% chance to completely resist damage.
2) When you have less than 200 mana, gain 50 mana.
1) Each attack will produce an additional 15 damage. Each attack will cause you to receive 15 damage.
2) When you miss, you have a 2% chance to reenter stealth.
1) Cooldown on all shocks is decreased by .5 seconds. Cooldown on all heal spells is increased by 1 second.
2) Each party member within 20 yards will regain 4 mana every 5 seconds.
1) +DoT spell damage
2) Your spells drain up to 10 hp from target. You regain up to 10 hp.
1) (this is the exception. each piece will be listed seperately, but without other stats which would accompany it)
a) Gloves: You cannot parry. +2% crit
b) Boots: You cannot dodge. +2% crit
c) Helm: You cannot resist spells. +3% crit
d) Chest: You cannot mitigate physical damage. +4% crit
2) 2% chance that any damage done to a party member within 15 yards will be done to you instead.