List of equipment that affects ability scores

This is a comprehensive list of equipment that affects ability scores.

Increases ability score

Equipment	Slot	Ability	Score Increase	Found in Act
Birthright	Headwear	Charisma	+2 (up to 22)	3
Duke Ravengard's Longsword	Weapons -  Versatile	Charisma	+2	3
Khalid's Gift	Amulets	Wisdom	+1 (up to 21)	3
Harmonium Halberd	Weapons -  Two-Handed	Strength	+2 (up to 23)	2
The Mighty Cloth	Armour - Light	Strength	+2 (up to 20)	2
The Graceful Cloth	Armour - Light	Dexterity	+2 (up to 20)	1
Nimblefinger Gloves	Gloves	Dexterity	+2 for gnomes +1 for halflings & dwarves	3
Dwarven Splintmail	Armour - Heavy	Constitution	+2 (up to 20)	2
Enraging Heart Garb	Clothing	Constitution	+2 (up to 20)	2
Gloves of Soul Catching	Gloves	Constitution	+2 (up to 20)	3
Devilfoil Mask	Headwear	Strength	+1 per nearby mask (Conditional)	1

Sets ability score to a certain value

Equipment	Slot	Ability	Score Value	Found in Act
Club of Hill Giant Strength	Weapons -  One-Handed	Strength	19	1
Gauntlets of Hill Giant Strength	Gloves	Strength	23	3
Amulet of Greater Health	Amulets	Constitution	23	3
Gloves of Dexterity	Gloves	Dexterity	18	1
Warped Headband of Intellect	Headwear	Intelligence	17	1
Handmaiden's Mace	Weapons -  One-Handed	Strength	18	3