Cracking boosters and relying on luck is probably not optimal if you know exactly what you want, so your best bet is to buy singles from online markets like TCGplayer
There was a period where every other deck in an online match would be an Articuno ex
Exemplar of Light As Elendas Hierophant taught us, giving flying to Ajanis Pridemate fixes one of its major problems: its weakness to getting chump blocked
Alternatively, you can sacrifice creatures for life gain
2 Typhlosion (17) Holofoil Market Price: $100.12 One of only two cards on this list to break the triple-digit threshold (and just barely at that), this card again shows the incredibly high value that fire-type starters have in the TCGs first two generations
Other times, maybe theres a card thats deterministically going to win the game, and in this spot, you have to act because everyone else knows you have the counter, so they wont act