Hm, I haven't considered that. Also, I myself haven't reached the pronouns section in my grammar book, so I still might discover something I don't know. But unless there's some tiny but disastrously important part, I think there's pronouns that can be used as a subject or an object - those you know in the nominative, accusative, and dative cases. Then there's possessive pronouns, which perform the same function as nouns in the genitive. So it would be mein, dein, sein, ihr... unser... and ihr, I think? And, of course, they take on different forms depending on where and what und so weiter.