Greetings, here's a list of every single Cosmogenesis Ending added by Hyperconstructs and More Primitives.
Regarding Gigastructures, the only new endings are the ones you receive from jumping into the Blokkat-Vester as far as I am aware of. Hyperconstructs adds one unique ending to Gigas as well though, as well as a few new Vanilla Cosmogenesis Endings.

New Vanilla Endings (requires Hyperconstructs):
- Federation's End
- Matter Decompressor Black Hole
- End of The Cycle Covenant (Pre-Reckoning)
- End of The Cycle Covenant (Post-Reckoning)
- Star Eater Black Holes


More Primitives Endings:
- Particle Accelerator Accident-Resulting Black Hole


Hyperconstructs Endings:
- The Dimensional Tearer Black Hole after an Exodus is completed
- The Dim. Tearer Black Hole after the Tearer has been destroyed OR a black hole resulting from a dimensional wave
- The Ruined Suprashell (Sparbelius System)
- The Ruined Edersphere (Kitkat System)
- Abyssal Anchor Black Hole
- Regular Black Hole Suprashell Black Hole
- Fallen Materialist Suprashell
- Interstellar System Creator-Black Hole

The following ones require the Reality Collapse Crisis to occur:
- Jump into the Ark's Generator
- Galactic Core during Reality Collapse x2 (Requires Fallen Spiritualists to exist)
- Basement Gateway Black Hole
- The Core of an Ark Cluster
- Any Black Hole of the Destroyed Galaxy


Additional Gigastructures Endings:
- Collapsed Star (Black Holes created by Gigas' Fusion Suppressors)

Enjoy finding them all :)
I really recommend the Matter Decompressor, the Destroyed Galaxy and the Ark'S Battery ones