5e Features as Magical Weapons and Items - Fighter

Fighter

Heartseeker - A weapon that would rather kill than wound. It scores a critical on attack rolls of 19 & 20. (Improved Critical)

Ring of Swiftness - This ring is forged from a mercury alloy, and bestows greater speed and reaction time to its wearer. While worn on the right hand, it allows it's wearer to act more swiftly; they can take another action when they choose, which is resolved at the end of a round. This ability is lost until the ring is worn for one hour on the left hand. (Action Surge)

Amulet of the Still Wind - An ancient talisman bestowed with the Wind of Peace. Once per day during combat, when the wearer forgoes attacking and moving, they recover 1d12 hit points. (2nd Wind)

5e Features as Magical Weapons and Items - Cleric

Shield of the Sun - This shield stores sunlight and releases it an a bright flash when the bearer is in danger. When the shield is charged, the bearer can force a reroll on a successful attack made within 10 feet. (Warding Flare)

Chromatic Staff - A stave carved from the wood of the world tree; it is imbued with the chaos of uncreation. At dawn, it's bearer can meditate on one of the forces of nature, and attune it to heat, cold, or lightning. Instead of bludgeoning damage, the staff deals damage of the attuned type. (Divine Strike: Nature)

Lightning Chain - This chainmail crackles with static electricity. When struck by a metal weapon, the bearer can release the stored charge into the attacker, dealing 2d6 lightning damage. (Wrath of the Storm)

Mace of Sympathy - A mace made entirely of metal, yet incredibly light. Some legends claim that these maces were forged from the Caduceus. When casting healing spell while bearing the mace, the user is healed a number of hit points equal to the spell's level (Blessed Healer)

Relic of the Conqueror - A finger bone from Ihdon, Lord of War. After spending ten minutes in prayer holding the relic, you receive Ihdon's boon. For the next two hours, you can invoke the boon to add +10 to an attack roll of you or your allies. Each time you invoke Ihdon, it has half the chance of succeeding as the previous invocation. (War God's Blessing)

Gravedigger's Lantern - The light from this bullseye lantern is not for the living. Shining it on a creature draws it closer to death. The next attack that strikes the target deals twice the amount of damage. Once the lantern is opened and the light is shone, it loses this property until it is left for one hour under moonlight. (Eye's of the Grave)

Codex Benedictum - The blessed book of knowledge has literally countless pages. If you spend 10 minutes searching through the pages, there is a 3-in-6 chance of finding information on whatever topic you are currently trying to find. (Knowledge of the Ages)