From Brotato Wiki
Fairy
Item
Tier 3
Stats
+1 HP Regeneration for every different Tier I item you have
-2 HP Regeneration for every different Tier IV item you have
-2 HP Regeneration for every different Tier IV item you have
Price
85
Unlocked by
Win a run with 
Renegade
RenegadeItem
Fairy is an in-game item that can be bought from a Shop or can be found in a Crate. Most Items modify the Stats of the player, and some of them provide additional effects.