Tier 1: The Yellow Prism Robes have some benefits and detriments.
Random Properties. This item has the following random properties:
• 2 minor beneficial properties (1. You gain proficiency with Wisdom (Insight) checks. 2. You can use an action to cast Sending. Once cast, roll a d6. On a 1-5, you cannot cast the spell in this way again until the next dawn.)
• 1 minor detrimental property (1. While attuned you must eat and drink 6 times the normal amount each day.)
Improved Arcane Ward. Your arcane ward now has hit points equal to twice your wizard level + your Intelligence modifier +10. In addition, when you cast an abjuration spell, your ward regains a number of hit points equal to twice the spell's level + 1.
Abjurer's Gift. Whenever you use your reaction to project your ward onto another creature, you can choose to grant that creature and your ward immunity to all damage. Once you use this feature, you cannot use it again until you finish a long rest.
Arcane Aegis. Whenever you cast the Shield spell, a number of creatures of your choice equal to your Intelligence modifier within a 15-foot radius of you, which can include you, gain a +1 bonus to their AC. This effect lasts until the start of your next turn.

Tier 2: The Yellow Prism Robes have additional benefits and detriments.
Random Properties. This item has the following additional random properties:
• 1 major beneficial property (1. Your Intelligence score increases by 2, to a maximum of 24.)
• 1 minor detrimental property (2. Your flaw changes to: “I am willing to do anything for the sake of increasing my knowledge".)
• 1 major detrimental property (1. Any turn you cast a spell your walking speed is reduced by 10ft. However, if you are using special movement (Flying, swim, etc.) your movement is cut in half (ex: cast fly, speed for that turn is only 30ft, not 60ft). If you already moved on the turn you cast a spell this effect applies on your next turn.)
Magic Guard. These robes now grant a +2 bonus to AC, instead of +1.
Superior Arcane Ward. Your arcane ward now has hit points equal to twice your wizard level + your Intelligence modifier + 20. In addition, when you cast an abjuration spell, your ward regains a number of hit points equal to twice the spell's level + 2. [2(x+2)]
Abjurer's Boon. While your ward is at 0 hit points, you have resistance to nonmagical bludgeoning, piercing, and slashing damage.
Weave Negation. Whenever you cast Counterspell against a spellcaster or a creature using a magical item and successfully counter their spell, you also momentarily block off their ability to manipulate the weave. The target is unable to cast spells until the end of their next turn.

Notes: abjuration wizard