Ring of Meta Gaming (5e Equipment)
From D&D Wiki
When this ring is worn by your character, they become self-aware, realizing that they are in a game of Dungeons and Dragons. You have 3 charges which can be spent to use this ring's features. All charges are recovered when the DM makes the decision to stop playing Dungeons & Dragons for the day (in real life).
Point out Flaw. If the DM has an unanswered question in his game, you can point out that plot hole. If the DM agrees that his or her game has a plot hole, you can use a bonus action to regain one charge.
Coin Flip. When you would make roll a die, you can choose to flip a coin instead. If you choose to do so, you can make a free action to toss a coin and call it. If called correctly, the die roll is treated as a natural 20 (or its highest value if it is not a d20). If called incorrectly, the die roll is treated as a natural 1 (or 00 if it is a percentile die). Using this feature expends one charge.
All-Knowing. You can use a bonus action to use a class feature, racial trait, or spell another willing creature knows, at the DM's discretion. Using this feature expends two charges.
Insanity. You can use a bonus action to go into a fit of absolute insanity, causing all creatures within a 50-foot radius of you to become Paralyzed and Frightened of you. Using this feature expends two charges.
Future Sight. You can use an action to ask your DM about any NPC or creature. The DM must reveal to you everything that you would like to know about that creature or NPC. The DM can choose to lie about this information, but if you correctly guess that he or she is lying, you can use a free action to summon a creature with a CR equal to your level. The summoned creature is friendly towards you and your party and obeys all orders you give it. The summoned creature rolls its own initiative and takes its own turns. Using this feature expends all charges.