Predecessor Builds > Phase > The Phase support build. (v0.6.1)

Crest - This is situational and you will be picking between Silentium, and Reclamation. If the enemy team has a lot of hard CC then reclamation is the way to go, but if they have a Gideon, Countess, or even Narbash. I heavily recommend Silentium, so you can shut down their ultimate's. If there's no hard CC or big team fight ultimate's you can go Leaf song, or Sanctification, these are great picks as well.

First item - I heavily recommend rushing Dynamo. The reason being is because of how the item synergizes with Phases kit, and enables the rest of your team to shred the opposing team. After phase casts energy lance the next instance of damage is buffed. This works really well with Dynamo because of the armor it shreds and the burst of damage it provides when the passive is procced. When you root an enemy, dynamo provides you with a damage buff from the protection shred. Stack that on top of the next instance of damage from energy lance and her passive, this makes her very poke heavy early.

The core buid - Dynamo, Hexbound bracers, and Tainted scepter. This is the all around general build I have the most success with.
Hexbound Bracers: Phases mana pool is very high and she rarely runs out. This allows for her to utilize hexbound bracers passive perfectly, giving her a good amount of CDR early.
Tainted Scepter: This provides good stats, and more CDR. Since you will need anti heal in most matches you can never go wrong with this item.

Situational items - Marshal: If you don't need to build anti heal marshal fits perfectly. This provides great utility in team fights from the attack speed aura, and also simply helps your team burn objectives quicker.
Vanguardian: Great mid to late game item to help keep your team alive and give them a little bit of survivability.
Timewarp: If you want to be more aggressive in the mid to late game, this item provides just that. With the CDR it provides it will help you stay in the fights longer and look for more
engagements/ setups for your team.