Druids have access to medium armor, but only if doesn't use metal. Thanks to a suggestion from Joshua Wardrop, I've decided to brainstorm some options for druids.
Angel Feather. Some druids are giving boons from devas serving their god, to either reward them or to signal that they are destined for something special. The armor is only designed for them and will not fit anyone else and fall into dust upon their death. It covers the body like scale mail.
Bulette Armor. Made of bulette hide and covers the body like half plate.
Dinosaur Scale Armor. Made of very types of dinosaur scales and covering the body like scale mail.
Giant Lizard Armor. Made of giant lizard scales and covering the body like a chain shirt.
Tortoise Shell Armor. Made of tortoise shells overing the body like breastplate.
Medium Armor Cost AC Weight Stealth
Angel Feather Special AC 14 + Dex (max 2) 5 lb.
Giant Lizard 100 gp AC 13 + Dex (max 2) 35 lb.
Dinosaur 150 gp AC 14 + Dex (max 2) 15 lb. Disadvantage
Tortoise 100 gp AC 14 + Dex (max 2) 15 lb.
Bulette 1000 gp AC 15 + Dex (max 2) 30 lb. Disadvantage