A Relic is an item that passively boosts one or more aspects of a character. Though the abilities of relics are extremely varied, they are generally powerful bonuses to one or more related statistics, many of which can be increased by no other means. A relic is different from an Artifact in that its use does not augment the user's Action Skill, is not restricted by class and may or may not be tied to a specific element. Relics appear only in Borderlands 2.
Common Relics
Vitality Relic - Boosts the character's maximum health by a percentage up to 50.
Allegiance Relic - Boosts a specific manufacturer's effects (reducing recoil, increasing damage, accuracy, reload rate, etc.). Can have a maximum of two effects simultaneously; both are applied to the same manufacturer.
Stockpile Relic - Boosts the munitions a character can carry of a specific class of weapons. Can also increase the maximum number of grenades a character can carry. Maximum of three can be increased simultaneously.
Protection Relic - Boosts the traits of the character's shield (capacity, recharge Speed, Recharge delay). Can have two bonuses maximum.
Aggression Relic - Increases weapon damage or fire rate with a specific weapon type (pistols, sniper rifles, etc).
Resistance Relic - Boosts resistances to one or several elemental or non-elemental damage types. Maximum of four resistances may be present.
Tenacity Relic - Improves the bleed out time in Fight for Your Life before death, and/or improves the health characters revive with after a Second Wind.
Elemental Relic - Increases damage dealt with a specific elemental damage type.
Strength Relic - Increases melee damage or reduces Override Cooldown Rate. Can have both bonuses.
Note: Override Cooldown Rate only affects Melee Override Skills with timers, e.g., Maya's Scorn ability or Salvador's Fistful of Hurt, so Zer0's Execute and Gaige's With Claws are unaffected.