| Harley Quinn X |
There are spells which increase stats by +4 for a temporary period. Not all of them are available to all types of casters though.
Strength: Bull's Strength (cleric 2, druid 2, paladin 2, sorcerer/wizard 2)
Constitution: Bear's Endurance (cleric 2, druid 2, ranger 2, sorcerer/wizard 2)
Dexterity: Cat's Grace (bard 2, druid 2, ranger 2, sorcerer/wizard 2)
Wisdom: Owl's Wisdom (cleric 2, druid 2, paladin 2, ranger 2, sorcerer/wizard 2)
Int: Fox's Cunning (bard 2, sorcerer/wizard 2)
Charisma: Eagle's Splendor (bard 2, cleric 2, paladin 2, sorcerer/wizard 2)
Also, like Wraithstrike said, don't get too caught up in what spells are used to make items. You can make those headbands and belts even if you don't actually know the spells. Just imagine a caster bending magic that they know to replicate the effects of a stat boost. Knowing a corresponding spell can make it easier to get the effect you want.