Bind Familiar

You gain the service of a familiar, a spirit (celestial, fey or fiend, each spirit has its own unique abilites) that takes the form of the corpse used.

Your familiar acts independently of you, but it always obeys your commands. In combat, it rolls its own initiative and acts on its own turn. A familiar can't attack, but it can take other actions as normal.

When the familiar drops to 0 hit points, it turns back into a lifeless corpse, but will reanimate in 1d20 hours

While your familiar is within 1000 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar's eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.

As an action, you can temporarily dismiss your familiar. It disappears into a pocket dimension where it awaits your summons. Alternatively, you can dismiss it forever. As an action while it is temporarily dismissed, you can cause it to reappear in any unoccupied space within 30 feet of you.

You can't have more than one familiar at a time. If you cast this spell while you already have a familiar, you instead cause it to adopt a new form.

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.

Celestial familliar abilities:

Divine Healing:the familiar may heal up to 30 points of HP per day with a touch, this amount may be split up between 1-30 creatures.

Stasis: If the corpse is able to be resurrected the celestial pauses and resets the deadline for resurrection, upon resurrection the creature becomes fully alive and mortal and the celestial is removed from the body,  unless the creature is sentient and allows it to stay, in which case the sentient creature retains the spirit's healing power and may take up the divine soul sorcerer subclass.

Fey familliar abilities:

Charming spirit: once per day the familiar can make any creature it touches make a DC 15 saving throw and on a failed save that creature is charmed and will not hurt the familliar or its master. The master and familiar (if it can speak) will have advantage on persuasion and deception rolls against the target, but disadvantage on intimidation.

Fey Time Dilation:

If the fey spirit is implanted into a corpse that is still eligible for resurrection roll a d8 multiply the result by the typical time period for resurrection, this is now how long you have to resurrect the corpse, starting from the summoning of the fey. If the corpse brought back to life the fey is forced out, unless the creature is sentient and chooses to let it stay at which point the resurrected creature retains its charming ability and may use the fey spirit as a warlock patron.

Fiend familiar abilities:

Fiendish flames:

The familliar may have 1 fire cantrip (damage dice determined by its master's level) and it may use it to engage in combat.

Fiendish Taint:

The corpse may no longer be resurrected, not even with a wish spell. If the familiar's master dies it keeps the body and may take levels, equal to its master's level in Wizard, Sorcerer (except for divine soul) or (Fiend patron) Warlock