Basically, while Pikachu ex doesnt have a ton of health and doesnt do as much damage as many of the best ex cards, their combination of reliability and speed allows them to get to their win condition quite effectively
Then you can put any number of Creatures onto the battlefield from your hand
Damage Opponents To further push the damage that Themberchaud can dish out, I added Fiery Emancipation
Likewise, MDFCs like Valakut Awakening dont make the cut on this list, as you should be playing MDFCs in all of your decks and they dont tend to encroach on deckbuilding slots like actual spells
In fact the printing of Unholy Heat (and to an extent Solitude) has mostly pushed out cards like Tarmogoyf out of the format, as the removal in the format is now so efficient that creatures either need to be one-mana, so you trade at an even level (Dragons Rage Channeler and Ragavan, Nimble Pilferer), too large to be killed by Unholy Heat (Deaths Shadow and Murktide Regent) or generate immediate value upon being played (Solitude, Fury and Omnath, Locus of Creation)