X & Y ONLY
Okay the most important items you need for IV breeding Pokemon are:
This item will pass down all IVs of the Parent that holds this. So If your parent Pokemon is has 31 attack IV's Give it a Destiny knot and the child Pokemon from the egg will have 31 attack Ivs aswell . Easy right?
This item passes down the nature of the parent holding it to the child egg much like the destiny knot. So if my Pokemon has a the right nature but not the right ability I can give it the ever stone and try to hatch for the right ability while being assured of the nature.
Give the child Pokemon 31IVs in the stat it helps train.
In XY, you can find Macho Brace lying on the ground at Route 15,
Power Weight (+HP)
, Power Bracer (+Atk),
Power Belt (+Def),
Power Lens (+SAtk),
Power Band (+SDef)
Power Anklet (+Speed)
can be purchased in Battle Maison (Kiloude City) for 16 BP each.
Nugget Bridge also have a good article on how to Breed for Perfect IVs
Hope this helped :)