Scuta Leather Armor

Best leather armor comes from Chult. Because dinosaurs!

• 135 gp
• Armor class: 13 + dex modifier
• Weight: 17 lb

Zorbo Hide Armor

The bad-tempered Koala-like Zorbo possesses the peculiar ability to transform his skin into whatever he’s standing on. Some clever leatherworker have figured out a way to craft an armor that keeps this amazing power.

• As leather armor but if you attach (bonus action) a special pin (comes with armor) it transforms into a (metal) breastplate.
• 600 gp
• you can buy an adamantine pin for 300 gp more (protection vs critical hits)
• Weight: 10 lb

Ankylo Breastplate

Astutely assembled from ridges, crests and bone-plates, this heavy apparel has the distinct advantage of being a lot less heat-inducing than its metal equivalent.

• 350 gp

And here’s something interesting: https://nhm.org/alternative-armor