The Channeling Companion suggests Ceremonies, Communal Ways, Death Mastery, Divine Magic, Life Mastery, and Proselytizing.
It might matter what your ancestors were like. Are you from a lineage that was very close to nature? Or an ancient line of guardians against a dreaded foe? That could color your relationship with your ancestors and the kinds of power they grant. If you don't want to leave it too open, you could at least think about what the Valenar elves are like (I have no idea so I can't comment specifically). If you want some room, you could have a limited number of options, e.g. ancestors who are primarily concerned with martial glory and honor, those that are primarily concerned with protection and healing, and those who focus on the intangible realm of the spirits themselves.