What feats or class abilities give an Int bonus to AC? Pathfinder or 3.5E material is OK. Please let me know what book you get it from!
Bladesinger (Complete Warrior p17):
Bladesong Style: When wielding a longsword or rapier in one hand (and nothing in the other), a bladesinger gains a dodge bonus to Armor Class equal to his class level, up to a maximum of her Intelligence bonus. If the bladesinger wears medium or heavy armor, she loses all benefi ts of the bladesong style.
This thread compiles a list of statistics and powers that use an unusual stat for the bonus, either replacing the existing statistic or enhancing it. This includes adding a statistic to AC, Damage, Hit, Saves, Spell DC and Bonus Spells.
Some 3.5 options (thanks to "snobi")
- Kung Fu Genius (Dragon #319, Dungeon Compendium Vol. 1)
You use your Intelligence modifier rather than Wisdom for all monk special abilities that normally rely on Wisdom.
- Carmendine Monk (Champions of Valor)
You can use your Intelligence bonus instead of your Wisdom bonus for determining your monk AC bonus and for determining the save DC against your stunning fist and quivering palm attacks. You can study your thesis notes for 1 hour to treat your monk level as two higher for determining one of the following monk abilities: unarmed damage, AC bonus, or unarmored speed bonus. This benefit lasts for 24 hours, at which point you can study your notes again to gain the same or a different effect. You can't study your notes more than once in any 24-hour period.
- Deft Defense (The Deft Fighter)
You now add your Intelligence Modifier to your Armor Class as a dodge bonus. This bonus is maintained under conditions that you receive your Dexterity bonus to Armor Class. This stacks with other dodge bonuses, unless that other bonus specifies otherwise. You cannot use this feat while wearing any armor with an Armor Check Penalty. Normal: Without this feat, you cannot add your Intelligence Modifier as dodge bonus to Armor Class.
- Ptah’s Cunning (Ronin - Book One - The Book of Days)
When wearing no armor, you may apply your Int modifier as a dodge bonus to your Armor Class. This improvement stacks with other dodge bonuses, but comes from your base, unaltered Intelligence score, ignoring temporary increases (such as those granted by the fox’s cunning spell). Permanent Intelligence increases, such as those gained through level advancement, do add to this benefit. Likewise temporary ability damage does not affect this feat, but permanent drain does. Any condition making you lose your Dexterity bonus to Armor Class also makes you lose dodge bonuses.
I'm surprised no one has put the duelist in there yet. One point of intelligence bonus for every level within the prestige class is added to dexterity for AC, however you can't wear armor or use a shield to get it. Starting at first level, too - requires BAB 6, Perform 3, Tumble 5, dodge, mobility and weapon finesse.
Invisible Blade (Complete Warrior p44):
Unfettered Defense (Ex): an invisible blade benefits from an increased survival instinct during combat. Because of this sixth sense, he adds 1 point of Intelligence bonus (if any) per invisible blade class level to his Armor Class in addition to any other modifiers he would normally receive. If the invisible blade is caught flat-footed or is otherwise denied his Dexterity modifier to Armor Class, he also loses this bonus. Unfettered Defense functions only when an invisible blade is not wearing armor and is armed with one or more daggers, kukris, or punching daggers as his only weapons.