Armor of Resistance
Armor (Any Light, Medium, or Heavy), rare, requires attunement · 2024 rules, SRD 5.2
You have Resistance to one type of damage while you wear this armor. The GM chooses the type or determines it randomly by rolling on the following table.1d10Damage Type1d10Damage Type1Acid6Necrotic2Cold7Poison3Fire8Psychic4Force9Radiant5Lightning10Thunder
Also in the 2014 rules (SRD 5.1).