What magic items can people suggest to gain Paladin or just Holy Knight abilities? Such as smite and detect or anything that give bonuses against evil (specifically demons/devils) creatures....
This is probably the closest thing to what you're looking for:
Bracers of the Avenging Knight
Price 11,500 gp; Aura moderate transmutation; CL 8th; Weight 1 lb.
These silver bracers are polished to a mirrored sheen, but otherwise shift their appearance to match whatever suit of armor they are worn with.
If the wearer has levels in a class that grants a smite ability (such as a paladin, or a cleric with the destruction domain), her smite damage is treated as though she were a member of that class four levels higher. If the wearer is not a member of such a class, once per day she may make one smite attack, gaining a bonus on the attack roll equal to her Charisma bonus, and a +5 bonus to the damage roll on a hit.
Construction Requirements
Cost 5,750 gp
Craft Wondrous Item, bless weapon
If you're looking for something against a single "Type (subtype)" of creature, like in this instance "Outsider (evil)", you're probably better off going with a bane weapon, though.
