Thinking about this further, and thinking about my efforts to make familiars more unique, I came up with this rough idea:
We take out this section:
And put in something like this (note this is a very rough idea / first draft):
Origin
When you first conjure your familiar, choose an origin from the list below (or a unique one with your DM's permission).
Original Form
When your Familiar drops to 0 Hit Points, it reverts to its Original Form. It becomes insubstantial, and cannot speak, communicate with signs, or interact with creatures or objects. It gains the Movement Hover 30, as well as a unique ability as described in the table below. Until you cast Find Familiar again, you lose any Bonus Features associated with your Familiar Bond, and cannot cast spells through your familiar. The familiar cannot regain Hit Points, and is only restored to its animal form when you cast Find Familiar again.
Origin | Original Form | Features |
Celestial | A glowing orb of blue, gold, or white light. | Familiar casts bright light for 15 feet and dim light for an additional 15 feet. |
Fey | A twirling swirl of leaves, fog, or flower petals. | As an action, the familiar may create illusionary sounds, as with the Minor Illusion spell. |
Fiend | A burning ember, emitting smoke, flames, or fiery bat wings. | The familiar emits a nauseating odor; creatures starting their turn in its space must make a DC 8 Constitution Saving Throw or gain the Poison conditioned until the start of their next turn. |