Breeding

 

The Gigalith line is part of the Mineral egg group. This means they can breed with : 

- Geodude / Graveler / Golem (and their Alolan forms)

- Onix / Steelix

- Sudowoodoo

- Nosepass / Probopass

- Snorunt / Glalie / Frosslass

- Trubbish / Garbodor

- Dwebble / Crustle

- Yamask (and its Galarian form), Cofagrigus, Runerigus.

- Vanillite / Vanillish / Vanilluxe

- Ferroseed / Ferrothorn

- Honedge / Doublade / Aegislash

- Klefki

- Bergmite / Avalugg (gen 8 only)

- Rolycoly / Carkol / Coalossal

- Cufant / Copperajah

-Stonjourner

- Duraludon

Notice : As Frosslass is only female, breeding with one will always give you a Snorunt, you can't get a Roggenrola  by breeding with a Frosslass as the baby takes the species of the female.

Moves they learn by breeding (gen 8)

Autotomize

- breeding with Steelix, Honedge, Doublade, Aegislash

Curse 

- breeding with Onix, Steelix, Yamask (and its Galarian form), Cofagrigus, Runerigus, Ferroseed, Ferrothorn, Bergmite, Avalugg

Gravity

- breeding with Stonjourner

Take Down

- breeding with Trubbish, Garbodor, Bergmite, Avalugg

Wide Guard

- breeding with Avalugg, Stonjourner

A Roggenrola egg takes 4080 steps to hatch.

Source : 

- Bulbapedia