A lot of things in life come down to a coin flip
Every time a set with Krenko is released, we see a small spike in the cards price as Magic players the world over are suddenly reminded oh yeah, this is the best possible goblin card ever created. Its not going to pay for your pack, but you can probably convince someone to trade for it
Teferis Protection takes the cake here, though, as its easily the best in slot
Cards like Fiery Emancipation, Thousand-Year Storm, and Niv-Mizzet, Parun can drop away with a touch of burn, and Izzet stalwarts like Goblin Electromancer, other spellslinger cards like Archmage Emeritus, and then a suite of blue countermagic can amp up the attack
Force of Vigor $6 I had Force of Vigor previewed for me a few hours before I stopped by Star City Games to check out its price tag, which led me to be pretty shocked when I found that it was pre-selling for less than $10