The Defender Plate is a chestplate armor added by Roots. The Defender Plate will automatically repair when equipped; each tick, there is a 1/80 chance of one durability being repaired, or a 25% chance of one durability being repaired per second. The Runic Tablet states it additionally "increases your [the player's] natural regeneration, even when out of food," but this appears to be untrue.
Fancy robes are nice and all, but sometimes you just want raw protection. The wildwood armor, built off of iron armor as a base, satisfies that purpose nicely. It has protection in-between iron and diamond armor, but also auto-repairs and increases your natural regeneration, even when out of food.