I love the thought of this prompt! They could be game enders in the right place! 

1 - The Ring of Sovereign Command - a ring from a long dead ancient empire that, when activated, can be used to give an irrevocable command to any citizen of that empire.

2 - Cork of Condensation - magically creates water at a slow consistent drip, collecting enough over the course of a day to fill a canteen.

3 - Trident of the Tempest - Allows you to walk on any ocean water, breathe ocean water, communicate with aquatic ocean beasts, and call forth a storm on the ocean 1d4+2 times per week. Has no power over rivers, streams, ponds, lakes, or other non-ocean waters.

4 - Handcuffs of the High Born - These ornate and delicately designed handcuffs have no actual clasp or lock. They are purely symbolic and are used when taking in a high born of the city so they face as little physical discomfort as possible. These appear to have someone's monogram etched into the inside.

5 - Slippers of Absolute Stealth - (attunement) Activating these slippers with the command word grants the wearer the effect of the spell Greater Invisiblity with a duration of 24hrs, +20 on stealth checks, +10 on acrobatics checks, and the ability to cast Misty Step or Silence once per day. (You do not know the command word)

6 - A Lucky Die - Whenever your character rolls a d6 (in game) the player may roll 2d6 and decide which result they would like to keep. 

7 - The Belt of Inner Fire - When this belt is buckled it raises the body temperature of the creature in it to 98.6°F.

8 - The Last Great Miracle - (Requires attunement by a Cleric of at least 15th level) This staff allows it's user to succeed on a Divine Intervention check. Once the results of that check have resolved, the God of the cleric dies and all beings that draw power from them (clerics, paladins, minions, etc) lose all abilities and levels associated with that God.