Amulet of the Gambler

Once on your turn, when you successfully deal damage to an enemy, gain one charge (maximum of 15 charges). Each time you gain a charge, roll a d20 and add your Proficiency Bonus. If the result is equal to or lower than the amount of current charges, all charges are instantly expended and you take Psychic damage equal to the amount of expended charges (no Reaction possible). As a Bonus Action or Reaction, you can expend all charges to give yourself or a creature within 30 feet of you Temp HP equal to the amount of expended charges for 10 minutes.

• While having 1-6 charges: You can use your Bonus Action to grant yourself or one creature within 30 feet of you a 1d4 to their next attack roll or saving throw. These benefits last until your next turn.
• While having 7-11 charges: You can use your Bonus Action to grant yourself or one creature within 30 feet of you advantage on their next attack roll or saving throw. These benefits last until your next turn.
• While having 12-14 charges: You can use your Bonus Action to grant yourself or one creature within 30 feet of you advantage to all their attack rolls and saving throws, a bonus of +5 to all their attack rolls, a bonus of 2d10 to one damage roll and resistance to all damage. These benefits last until your next turn. You can use this particular effect only five times in a charge period before all charges are expended automatically.
• While having 15 charges: You automatically expend all charges and can grant yourself or one creature within 30 feet of you the benefits of a long rest in addition to the previous effect.