I think one of the best current builds that you can carry on if you're going to play Io with Goddess.

Constant solid heals and DR while you stay close with Luna to regain more moonlight (even more if you're not using it).

About her shop items, I always prefer nimble 3 at the start, as you can get it at max really quick while also buying defense items like haven and blast shields afterwards (depending of which type of damage you're struggling more).

Resilence and illuminate are also great defensive items to go for, but as we'll see later, only situational based on the enemy team's composition.

Other items like wrecker and bulldozer are highly recommended for Io too as she has fast fire rate so she can deletes shields and deployables.

But obviously, they're still situational items to go for if you don't need them.

Kill to heal is also a great option to buy as it can offer you extra auto sustain when fighting against most damages and flanks.

The secondary build that I don't use often is the DR + Speed.

Not much to say about this one, as you can also give movement speed while healing and giving DR, but you have to be more careful as Io can struggle more to heal with moonlight and survive with this build, so I recommend you to change some cards as you like to feel more comfortable.

That also goes the same for shop items with that build.