The unfinished, but canon, Star Wars: The Clone Wars arc Crystal Crisis on Utapau features a giant green kyber crystal.
Yoda mentions how giant kyber crystals were used in ancient super-weapons:
Long ago in forgotten times when the Sith and Jedi fought for control of the galaxy, weapons there were of unimaginable power. Always at their heart a kyber crystal was.
It's also heavily implied that a similar crystal was later used in the Death Star. The canon novel Tarkin confirms this.
The designers are also debating the optimum configuration for the Kyber crystal assembly.
Additionally, The First Order Star Destroyer Finalizer, and possibly other First Order Star Destroyers used kyber crystals in their turbolasers.
Her turbolasers are more powerful and faster to recharge than Imperial-era weapons, a product of kyber crystals harvested in the Unknown Regions.