As I see it there are a number of optimal choices.
Miss Martian can make herself invisible (good for not having to explain things) read and control minds (get money and more slaves) and shape shift. A good choice if ethics don't bother you and you don't plan on living forever or have another way to do that.
Assuming
>>83478258 is right about Zatanna being able to make you an immortal god she is probably a safer bet than Wanda (who no longer has House of M level power) but both are good. Also consider Sabreena the teenage witch.
Magic has a personal dimension that she could hand over to you (I don't know what powers you gain from owning Limbo but it's something to consider) and can travel through time and space should you have need of it.
X-23 is use to following orders, will heal quickly and can give concise answers. A good simple choice.
Death (DC Sandman) is cute and can stop anyone from aging or dying as well as being able to kill anyone you want.
Kobik is a Cosmic Cube but under age.
Captain Universe can power you up or find others willing to satisfy your lust but doesn't seem to control her/it's host. May not count but could bypass the slavery is wrong argument.