Main Loadout(Solo Healer Io):
This is my Main Loadout, Normally i run Max nimble on io with either caut or master riding as the second item, the 3rd and forth slot will either be resil haven or blast shields depending on the enemy team Comp, i highly avoid running chronos unless you are running Life Link Io, which will be in a separate build, my go to talent is goddess blessing, goddess blessing is the best talent for io since the DR from her moonlight cannot be countered unlike Luna healing. The DR from Goddess Blessing could save a lot of your teammates from death and i managed to pull pretty high heal numbers with this loadout. Sanctum of Faith and Moonwalk are a must have in any io loadout because these cards can help maximise your heal potential, i put crescent to escape from any flanks, if you have good aim i suggest using moonlight garden as you generate moonlight after healing an enemy and restored faith as a filler card.
Life Link Loadout:
I see many Io Players use Life Link which is fine but personally i think Goddess Blessing is Way better but different people have different playstyles so heres a life link loadout, for items i suggest using Chronos and nimble, Chronos to get your luna up more often and nimble for escaping and movement. I assume if you run Life Link, your luna will be around you most of the time which is why i suggest to use Protectors at Level 3 and Spirits arrows to constantly heal around the Luna at level 4, Moon walk level 4 for capacity, i put moonlight garden as a filler card but you can also use crescent or the card that increases luna deploy if you want, this build is what suits me but feel free to change
Fun Builds:
I have two Fun builds for Io, one called the flying io and one that Buffs allies speeds while also maintaining good heals Items i suggest are Nimble(Always) and Caut for both builds, any talent for the flying io build, goddess blessing for the speed WARNING; Do Not use the fun builds in Ranked, also have a another healer if you are using these builds in casuals

Nimble
Armor
Gain 21% Movement Speed.
Level 3

Level 3

Goddess' Blessing
Moonlight
Allies being Healed by Moonlight take 15% reduced damage.
Level 3

Sanctum of Faith
Moonlight
Regenerate 5% Moonlight every 1s while not using Moonlight.
Level 5

Moonwalk
Armor
Increase your maximum Moonlight capacity by 32%.
Level 4

Moonlight Garden
Weapon
Generate 6% Moonlight for each enemy hit with Light Bow.
Level 3

Crescent
Lunar Leap
Reset the Cooldown of Lunar Leap after dropping to or below 45% Health.
Level 3

Restored Faith
Moonlight
Heal for 10 every time you Heal an ally with Moonlight.
Level 1

Moonwalk
Armor
Increase your maximum Moonlight capacity by 32%.
Level 4

Spirit Arrows
Moonlight
Reduce the Cooldown of Luna's redeploy by 0.4s after healing with Moonlight.
Level 4

Sanctum of Faith
Moonlight
Regenerate 3% Moonlight every 1s while not using Moonlight.
Level 3

Protectors
Guardian Spirit
Regenerate 6% Moonlight every 1s while within 30 units of Luna and not using Moonlight.
Level 3

Moonlight Garden
Weapon
Generate 6% Moonlight for each enemy hit with Light Bow.
Level 3

Chronos
Armor
Reduce the Cooldown of all your abilities by 30%.
Level 3

Nimble
Armor
Gain 21% Movement Speed.
Level 3

Life Link
Guardian Spirit
[Guardian Spirit] Luna Heals allies around her for 320 per second. Reduce Moonlight's Healing to 135 every 0.15s.
Level 3

Moonwalk
Armor
Increase your maximum Moonlight capacity by 40%.
Level 5

Swift Arrows
Moonlight
Increase allies' Movement Speed by 24% while they are being Healed by Moonlight.
Level 4

Moonlight Garden
Weapon
Generate 6% Moonlight for each enemy hit with Light Bow.
Level 3

Crescent
Lunar Leap
Reset the Cooldown of Lunar Leap after dropping to or below 30% Health.
Level 2

Sanctum of Faith
Moonlight
Regenerate 2% Moonlight every 1s while not using Moonlight.
Level 2

Goddess' Blessing
Moonlight
Allies being Healed by Moonlight take 15% reduced damage.
Level 3

Swift Arrows
Moonlight
Increase allies' Movement Speed by 6% while they are being Healed by Moonlight.
Level 1

Sky-Walker
Armor
Lower your gravity and increase your air control by 40% while firing your Light Bow.
Level 4

Crescent
Lunar Leap
Reset the Cooldown of Lunar Leap after dropping to or below 60% Health.
Level 4

Half Moon
Lunar Leap
Reduce the Cooldown of Lunar Leap by 4s.
Level 5

Moonlight Garden
Weapon
Generate 10% Moonlight for each enemy hit with Light Bow.
Level 5

Sacrifice
Guardian Spirit
[Guardian Spirit] If Io falls below 200 Health while Luna is active, she trades places with Luna, Heals for 50% of her Health, and Luna dies in her stead.