Fun and pretty decent deck.
Stoutland in the front, Raticate in the back to steal energies. Koraidon comes in at the end to deal larger damage if necessary.
One of the Sabrinas can be exchanged for a Repel. May is helpful, but can be exchanged with other tech cards (Dawn/Iono/Cheren/Lillie/Red/Arena of Antiquity/etc).
Koraidon also gets to benefit from Rainbow Cave! Cave + Sada gets Great Tusk attacking turn 1, making this list much better than before.
This list commits to this strategy fully, and as a result cannot use Arena of Antiquity. (Which is ok, as long as Great Tusk can attack turn 1 to apply early game pressure with its high damage). This list has 3 really high HP Pokémon, so games will be LONG, meaning no arena is mostly a non-issue.
Klefki is here so the chances of leading Koraidon are lessened.