Like most Magic: The Gathering cards, the value of Karlach, Fury of Avernus depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Commander Legends: Battle for Baldur's Gate)
Unlike the list of rarest Pokemon cards I shared, there is more stability to what everyone refers to as the most valuable when it comes to MTG (with some exceptions, which Ill detail below)
Using cards that can give you extra coin flips is perfect because you only really need two heads to make the effect go off properly
The Flesh Is Weak The Flesh Is Weak is the perfect Esper card for artifact archetypes that focus on generating a large quantity of tokens
At the beginning of your combat only, you'll make a free Food you can sac for life and triggering Frodo
When theres nothing left to grind, the game will start to feel boring, and theres no fun in that