Fire Sages Fire Sages' red mana generation is cool, but being able to use that mana to power itself up--assuming you can pay the rest of the ability cost--could turn it into a powerful attacker in a hurry
The four-mana enchantment-themed planeswalker is certainly interesting, but is much more of a build-around than a typical powerful planeswalker that could easily slip into any deck of the matching colors
Sun & Moon Team Up is primarily Kanto focused, but because Dark-types didn't exist when Kanto was created, there isn't anything to pull from there
For example, its been built into Lost Zone decks (pre-rotation) to give us another archetype in the meta
The Pokmon Celebrations mini-set was mostly a collectible one with few competitively viable cards, and Flying Pikachu was likely intended to be nothing more than a fun tribute to the fan-favorite Flying Pikachu card first released in English as a promo in 2001, which is why fans are so tickled by the fact that it literally just won the Pokmon TCG World Championship
Other cards you might want to consider adding to the decklist are the following: Snorlax VIV: This Pokmon got really popular at the beginning of the Battle Styles format as it was the perfect way to set up in the first turn thanks to its ability