Zamazenta and Cobalion, in combination with Metagross, are the backbone of your later turns
Its solid ATK and DEF made it a strong card in the TCG's early years, though these alone aren't enough to keep it competitive in the modern day
Then come back and read the rest
Red often requires you to discard as part of the bargain, sometimes giving you card "selection" but not actually card "advantage." Black is the most likely to cost you life and White is just the worst, often having to rely on shutting down an opponent's extra draw in order to get your precious extra cards
Arceus ex and its associated cards can be powerful with the right list, as can Garchomp ex, but theyre not best in class
This color pair probably more than any other rewards you for going deep on one of the two colors, since both have potent common Devotion rewards