
Free Agent - EU
These are my build, I hope they will help you find the perfect loadout for your Io! As a tip from a Io main I suggest to try every build before saying something bad about them <3 Some of them are more useful than others but the player's playstyle matters too!
Casual=all "quick play" game modes
Rank=it's a siege game but you're going to cooperate more with your team
The best talent for Io :3

Goddess' Blessing
Moonlight
Allies being Healed by Moonlight take 15% reduced damage.
Level 5

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

Swift Arrows
Moonlight
Increase allies' Movement Speed by 18% while they are being Healed by Moonlight.
Level 3

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

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

Moonlight Garden
Weapon
Generate 10% Moonlight for each enemy hit with Light Bow.
Level 5
For this build you need to have on the enemy team a beefy tank or a tank with deployables / shield / wall AND NO COUNTERS, for a faster moonlight regeneration (12% per second)! You can also use it when your team has another healer, but you might want to change some cards or levels because of your team/enemy comp or map!
Cards:
Sanctum of Faith (level 2) - Regenerate 2% Moonlight every 1s when not using Moonlight.
Swift Arrows (level 3) - Increase allies' Movement Speed by 18% while they are being Healed by Moonlight.
Moonwalk (level 4) - Increase your Moonlight's capacity by 32%.
Restored Faith (level 1) - Heal for 10 every time you Heal an ally with Moonlight.
Moonlight Garden (level 5) - Generate 10% Moonlight for each enemy hit with Light Bow.

Goddess' Blessing
Moonlight
Allies being Healed by Moonlight take 15% reduced damage.
Level 5

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

Spirit Arrows
Moonlight
Reduce the Cooldown of Luna's redeploy by 0.30000000000000004s after healing with Moonlight.
Level 3

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

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

Moonlight Garden
Weapon
Generate 10% Moonlight for each enemy hit with Light Bow.
Level 5
Well for this build I have the same requirements as for "Speed Heal"! Let's say you have only one tank and you're the only healer of the team. You can place Luna to help capture the point or zone out the enemy players that can get stunned.
Cards:
Sanctum of Faith (level 2) - Regenerate 2% Moonlight every 1s when not using Moonlight.
Spirit Arrows ( level 3) - Reduce the Cooldown of Luna's redeploy by 0.3s after Healing with Moonlight.
Moonwalk (level 4) - Increase your Moonlight's capacity by 32%.
Restored Faith (level 1) - Heal for 10 every time you Heal an ally with Moonlight.
Moonlight Garden (level 5) - Generate 10% Moonlight for each enemy hit with Light Bow.

Goddess' Blessing
Moonlight
Allies being Healed by Moonlight take 15% reduced damage.
Level 5

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

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

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

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

Protectors
Guardian Spirit
Regenerate 10% Moonlight every 1s while within 30 units of Luna and not using Moonlight.
Level 5
I think everyone should have a "Counter" loadout! In casual can be very useful because you can't see what the enemy team is picking, but in rank really depends...
Cards:
Sanctum of Faith (level 3) - Regenerate 3% Moonlight every 1s when not using Moonlight.
Swift Arrows (level 1) - Increase allies' Movement Speed by 6% while they are being Healed by Moonlight.
Moonwalk (level 5) - Increase your Moonlight's capacity by 40%.
Restored Faith (level 1) - Heal for 10 every time you Heal an ally with Moonlight.
Protectors (level 5) - Regenerate 10% Moonlight every 1s while within 30 units of Luna.
With this talent you can go for a hybrid build

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 5

Protectors
Guardian Spirit
Regenerate 10% Moonlight every 1s while within 30 units of Luna and not using Moonlight.
Level 5

Broken Deity
Guardian Spirit
Increase Luna's deploy range by 20%.
Level 1

Moonwalk
Armor
Increase your maximum Moonlight capacity by 24%.
Level 3

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

Moonlight Garden
Weapon
Generate 10% Moonlight for each enemy hit with Light Bow.
Level 5
You can deal damage and heal at the same time multiple people if you can position Luna in a safe spot! You also have 20% moonlight regeneration :p I used it the most in Onslaught and IT'S THE BEST FOR A HYBRID IO IN SOME MAPS >;3