If it does start the game in your sideboard, consider bringing it in against green decks, too, as this messes with their bite cards in a serious way
Maybe well get some crazy powerful new Moana cards although anything stronger than Maui Half-Shark seems almost absurd
In fact, older collections stored in ring binders often show telltale circular indents or crimps on cards where the rings pressed down
Based on the latest market prices tracked on TCG Stacked, Stonehoof Chieftain is worth about $2.34 USD for a regular copy and $2.27 USD for a foil copy
While Dobermon's sacrifice gives Takato, Henry, Rika, and Ryo the ability to BioMerge with their partners in the real world, and become Gallantmon, MegaGargomon, Sakuyamon, and Justimon, it doesn't give them any protection against the D-Reaper, and its ability to delete anything it touches
Since it costs five mana, Karn is guaranteed to be at least a 5/5 at all times