Familiar: Requires a CL of 3, take Obtain Familiar.
Animal Companion: Spell-Less Ranger (CW) grants it.
Psicrystal: Requires an ML of 1, take Psicrystal Affinity.
Leadership: Requires ECL6, pick up 1/e you want.
Wild Cohort (
online): Can be taken at the 1st level, pick an animal.
Shape Soulmeld (soulspark): Can be taken at the 1st level, gives you a pew-pew ball of light.
Purchase an Animal: A&E really expands on this area, it's a pet, it doesn't grow, but who cares right?
Buy a slave: I think LoM is the source on this, buy humans. Keep them chained up or they run away.
Dominate: Always a good route.
Animate: Sometimes even better!
Fission -> Metamorphosis:
Be your pet.
Mind Rape: 2nd best option.
Ice Assassin -> Shapechange: Is there anything this won't solve?