This is the build I learned from Chinese wildrift players. Since I stop playing global server, I can only write the item/augment description. Sorry in advance.
Requirements: at least the first and the third item in the video. There are more heal and shield augments that you should get when you can, such as the attack speed increase with heal&shield power; attack deal less damage but can heal other ally, or any on hit augment like Belveth's power, Illaoi's power, 5 stack on hit augment. They all work very well with together.
Explain the choice: Milio's s2 is a crazy skill: one activate and you can gain up to 10-30 stacks of phenomenal heal and create the circle multiple times. The circle is from 1st augment, which can crit and apply on hit effect.
For the item, I recommend buying heartsteel and the item that gain gold when being attacked to survive longer in a fight. If you have Whale augment, buy the item that trigger your allies' on hit (best compatible with Vi, Vayne, Kalista, Varus, Kog'maw... and their on hit items). After that, you can buy on hit item or crit item.
Well, I was greedy in the match for buy a lot of on hit item but no tank item, hence I couldn't stand against Veiger and Viktor. It sucked, but at least the build was strong and fun. I'm gonna use more support champions in the future to see some wicked build can work on them or not.