As you can see, a majority from Abyss and Nebula's mom's side are spacial gods and are at least seen, but their identities are still unknown.
On Abyss and Nebula's dad's side on the other hand, it's only Rocket, Rocket's dad Nightmare, and Nightmare's mom Gaia, Rocket's mom and grandpa are nowhere to be found.
So unlike Emerald's family tree where most of her relatives are visible, most Abyss and Nebula's are unknown and they have never even known of Abyss and Nebula.

#G522FT