2 Biogenic Upgrade Uncommon - $3.29 Counter strategies are a very fun deck to build, and Biogenic Upgrade gives you a neat way to let those counters spiral out of control
Creature (36) 2x Carnage Tyrant 3x Druid of the Cowl 2x Ghalta, Primal Hunger 1x Gishath, Sun's Avatar 3x Goring Ceratops 4x Kinjalli's Caller 1x Otepec Huntmaster 2x Polyraptor 1x Raging Swordtooth 2x Ranging Raptors 1x Regisaur Alpha 3x Siegehorn Ceratops 3x Steadfast Armasaur 3x Territorial Hammerskull 1x Thundering Spineback 1x Wakening Sun's Avatar 3x Zetalpa, Primal Dawn
After that time, the prices for unplayable cards plummet, while playable cards usually maintain their value, at least when sold from Japan
You can also spend five mana to pump your team by a Glorious Anthem each, so that's very strong here
Naturally Powerful Considering how simple it is to enable Oskar, its surprising that the card doesnt see more play