Amber and Amethyst are a great combo with cards like Lilo Making a Wish, and Maleficent Biding Her Time, as they both are amazing 1-cost cards with 2 lore each
Basically, it doubles your chances with every coin flip, and thats the kind of thing thats going to supercharge your deck, and make it slightly less about luck, and slightly more about winning a lot
So a card like that cost ten Chernabog
4th Amethyst Steel Patrick Cote 1 Belle - Accomplished Mystic 3 Calhoun - Marine Sergeant 4 Chernabog's Followers - Creatures of Evil 4 Diablo - Obedient Raven 4 Doc - Bold Knight 4 Elsa - The Fifth Spirit 1 Friends On The Other Side 4 Genie - Wish Fulfilled 4 Madam Mim - Fox 4 Madam Mim - Snake 4 Magic Broom - Illuminary Keeper 3 Merlin - Crab 4 Merlin - Goat 4 Mr
This has a passable baseline and the useful artifact type, and it can maintain relevance once you reach the late game
The stats aren't nothing either, as a 1/4 can block a lot of things