More or less in order, the unity of
1.) the unity of the persons in Trinity
2.) the human nature and divine person in Christ.
3.) the indwelling of the Trinity in the soul by grace
4.) active and passive creation
5.) the knower and known
6.) the powers of intellect and will in the intellectual soul.
7.) essence and existence in a creature
8.) matter and form.
9.) substance and proper or essential accident
10.) substance and quantity, then quality, then the rest of accidents.
a.) the angelic wills in friendship
b.) angelic wills in illumination of a superior to inferior.
c.) friendship between persons by sacrament
d.) friendship between persons according to virtue, then pleasure, then utility.