*Also here is a short reminder on damage mitigation. The value of the mitigation can be subtracted from incoming damage when applicable. (Example: 3 general mitigation means if you were hit for 5 piercing, then you would take 2 piercing damage.)
Light Armor
Padded. AC = 12. 8 lb. 5 gp
Leather. AC = 11 + Dex modifier. 10 lb. 20 gp
Studded Leather. AC = 12 + Dex Modifier (max 2). 13 lb. 50 gp
Medium Armor
Hide. AC = 12 + Dex modifier (max 2) 12 lb. 100 gp
Chain Shirt. AC = 13 + Dex modifier (max 2) 20 lb. 150 gp.
Scale Mail. AC = 14 + Dex modifier (max 2) 45 lb. 175 gp
Spiked Armor. AC = 14 + Dex modifier (max 2) 45 lb. 200 gp
Breastplate. AC = 14 + Dex modifier (max 2) 20 lb. 500 gp
Halfplate. AC = 15 + Dex modifier (max 2) 40 lb. 800 gp
Heavy (while wearing heavy armor you have disadvantage on dexterity rolls unless it posses a magical trait indicating it does not receive this penalty.)
Ring Mail. AC = 14 + Con modifier (max 2). 40 lb. 600 gp
Chain Mail. AC = 16 + Con modifier (max 2). Str 13 required to wear this armor. 55 lb. 750 gp
Splint. AC = 17 + Con modifier (max 2). Str 15 required to wear this armor. 60 lb. 1100 gp
Plate. AC = 19 + Con modifier (max 2). Str 16 required to wear this armor. 65 lb. 2000 gp
These armor types can also be made out of different common-ish metals just like weapons. Below those materials are listed and with their benefits and additional costs.
Copper / Bronze / Tin is no benefit and normal.
Iron adds +1 to AC (+20-40 g cost)
Silver add +1 to AC and 1 damage mitigation to necrotic and fire damage. (+60-100 g)
Steel / Tungsten adds +2 to AC and 1 damage mitigation. (+40-90 g cost)
Malchite (stone from the planes of hell and far in the underdark) adds +2 to AC and 2 damage mitigation against radiant damage. (+100-200g cost)
Mithril / Palladium adds +3 to AC and 2 damage mitigation. (+200-300g cost)
Adamantine / Orichalcum adds +4 to AC and 3 damage mitigation. (+300-500g cost)
Orochite / Tenecite / Daxite adds +4 to AC and 3 damage mitigation. All of these three are innately magical.
Orochite gains an additional 4 mitigation to magical attacks. It is easily identified by its unique orange-gold shine. It magical traits require the use of magic to craft. (+500-2000g cost)
Tenecite gains an additional 4 mitigation to natural attacks (unarmed or claws for example). Tenecite is a dormant form of an old virus called Tenecyte. It can be forged with like a metal once the tenecyte becomes tenecite. (+600-2000 g cost)
Daxite can not be altered through spells. It gains an additional 5 mitigation to magical attacks. Its a dark hyper dense material that is very difficult to craft with due to the extremely high level of heat required to do so. (+650-2600 g cost)
Etheral adds +5 to AC and 15 mitigation. It is resistant to all non-magical physical attacks and can defend against Devine forces. Etheral is considered extremely magical and can be identified easily by a DC 14 arcana check from any caster. Etheral Armor can only be made into medium armor and light. (+4000 or more g cost)
Void Metal is a hyper dense metal that can only be forged with extreme magical talent and is very rare. It provide +6 to AC and 10 damage mitigation. It is resistant to all elements and can defend against devine forces unlike most armors. It can not be perceived as magical but is still easily identified due to its uniqueness. Its dense nature makes it so that it can not be made into heavy armor, as it would crush its wearer. This extreme weight is also why it can not be made into a weapon. (+6000 or more gold in cost)
There are also some non-metal materials that can be used to make armor...
Wyrmwood a strange magical plant that seems to attract draconic creatures. This armor can be made into only light armor. It provides an additional +1 to AC and 2 damage mitigation. It is resistant to all elemental attacks from evolving around dragons. (+400 g or more)
Dragon Hide is obtained by many hunters. This armor provides an additional +2 AC and 5 damage mitigation. It is resistant to damage corresponding to the dragon's breath weapon. If it was a fire breath, then fire resistance. (+400 g or more).
Falmer Chitin is actually a misnomer. It is chitin made from the different types of Kamikiri, magical arthropods. It is difficult to obtain and provides immense benefits. It provide +3 AC, 5 damage mitigation, and +2 to all stealth rolls. It is also resistant to poison and acid damage. It can not be made into light armor due to its thick formation. (+800 g or more)
Hive Bone is obtained in 2 ways but one is highly frowned upon. The first is by harvesting it from the victims of the bone hive plague. The second is by creating it from the husk of the fundament krill, also known as hive. It provides +3 AC, 2 damage mitigation, and resistance to necrotic and acid damage. (+700 g or more)
Runed Sizing: This is an effect that can be added to armor and allows the armor to change size with the wielder. It adds 100-200 gold to the value of an armor set.
Thane's Spite: This magical forge effect deals 1d6 slashing damage to any who touch the outside of the armor. It adds 75-160 gold to the value of a set.