Either:
-5x Julianos: Crafted and reliable. Use this to start your grind for dropped healer sets below.
-5x Spell Power Cure: The best support set out there at the moment. Gives up to 6 players a 250 Weapon/Spell damage buff which has a big impact in trials where you have 8 or 9 DPS hammering away.

Either:
-5x Infallible Mage: The 8% extra damage given to everyone on your team by heavy attacking with this set is insanely good in group and raid content. With the change for Concussed, this set isn't as depended upon, but its still good in certain setups and group dungeons.
-5x Worm's Raiment: Reducing Magicka costs matters more now than it used to since Homestead changed Magicka return. Pretty much mandatory for groups now that Magicka is one sided in trials.
-5x Twilight's Remedy: Didn't like this set before Homestead but with the changes to Minor Vulnerability it gains priority over Infallible Mage now. Used in boss fights alongside worm.
-5x Mending: This set affects enemies in trials and is actually great. Use it alongside another healer running worm and you'll have an easier time getting good vitality bonuses.

Master's Restoration Staff: This staff provides a bunch of stamina to all allies affected when you spam Healing Springs and works with any build. This staff has no rival in terms of what it gives your team.
Master's/Maelstrom Destruction Staff: Get one of these if you can if you are running Elemental Drain or Infallible Aether. Lightning is the best choice for element, followed by Fire, but Ice is fine aswell.