Luck of the Draw

At first glance this appears to be a standard 52 card deck of playing cards. Those with a keen eye or sense for magic would notice nearly invisible runes or glyphs written into the back of each card depicting the sacred symbol of Lady Luck. This deck is unique even amongst items within Lady Luck's domain for the simple fact that there doesn't seem to be an innately negative outcome. The deck simply brings varying degrees of good luck in one way or another.

Drawing upon the power of the deck can augment the abilities of either the individual drawing, or the individual being drawn for. This distinction must be established before the act of drawing a card.

This is a unique magical artifact, created by Lady Luck for a favored devotee, and should be treated with the respect one would bestow upon the Goddess of Luck herself, for if anything should not be taken for granted, it is Luck.
(Designed with D&D5e in mind)

In Combat

In Combat the user may use a bonus action to draw a card, granting its effects to either themself or an ally, established before the drawing of the card, for the duration of combat. Only 1 in-combat card may be drawn per ally, including the drawer, per combat. The cards have the following benefits:

Hearts - Temporary HP
2, 3, 4, 5 - A number of Temporary Hit Points equal to the affected person's Proficiency Bonus
6, 7, 8, 9 - A number of Temporary Hit Points equal to Double the affected person's Proficiency Bonus
10, J, Q, K - A number of Temporary Hit Points equal to Triple the affected person's Proficiency Bonus
Ace - A number of Temporary Hit Points equal to Quadruple the affected person's Proficiency Bonus

Diamonds - AC
2, 3, 4, 5, - 1 additional point to Armor Class
6, 7, 8, 9, - 2 additional points to Armor Class
10, J, Q, K - 3 additional points to Armor Class
Ace - 4 additional points to Armor Class

Clubs - Damage Roll
2, 3, 4, 5, - 1d4 additional points to Damage Rolls
6, 7, 8, 9, - 2d4 additional points to Damage Rolls
10, J, Q, K - 3d4 additional points to Damage Rolls
Ace - 4d4 additional points to Damage Rolls

Spade - Attack Roll
2, 3, 4, 5, - 1 additional point to Attack Rolls
6, 7, 8, 9, - 2 additional points to Attack Rolls
10, J, Q, K - 3 additional points to Attack Rolls
Ace - 4 additional points to Attack Rolls

Out of Combat

Out of Combat, the user may draw a card, granting its effects to either themself or an ally, established before the drawing of the card, which lasts 3 hours. Only 1 out-of-combat card may be drawn per ally, including the drawer, per long rest.

The Suit determines the affected type of Skill Checks, while the number determines the severity of the effect.
Hearts - Charisma Checks
Diamonds - Wisdom Checks
Clubs - Intelligence Checks
Spades - Strength/Dexterity Checks

2, 3, 4 - Add half of your Proficiency Bonus, Rounded up, to related Skill Checks.
5, 6, 7 - Add your Proficiency Bonus to related Skill Checks.
8, 9, 10 - Add double your Proficiency Bonus to related Skill Checks.
J, Q, K - Gain Advantage on, and add your Proficiency Bonus to, related Skill Checks.
Ace - Gain Advantage on, and add Double your Proficiency Bonus to, related Skill Checks.

Item type

Unique Artifact