My favorite hair oils are:
Ranavat Mighty Majesty fortifying hair serum - I apply this once a week the day before I wash my hair and massage it well in my scalp. It really helped recondition my gray hair from wiry to soft. I also use this to slick back my ponytail without hairspray.
I apply either the Verb or Kerastase oil to my ends when my hair is damp.