1st edition packs of pokemon cards Base Set Booster Pack Shadowless style promo cards consisting of beloved first partner Pokemon from the Kanto 1st Edition - Old Pokemon

Definitely a money rare

There are even pseudo-combos available with cards like Sheoldred, the Apocalypse and Queza, Augur of Agonies, where you can draw as deep as your mana allows

The S9 Charizard V SA (103/100) is widely regarded as the best Charizard illustration in the era

Through the Omenpaths are mechanically identical cards of entire sets that get different art and names

Aura/equipment decks can benefit from some of the robots above like Codsworth, Handy Helper

We'll fix things up in the upgrades section but there isn't much more to work with, which is either a good thing because you can "finish" the deck after a round of upgrading or bad because most sets won't have anything for your theme