The Meowth Promo in English has replaced it with the classic Black Star Promo icon and moved GB onto the actual artwork in the bottom right-hand corner
Frank's calculations assume the pre-london mulligan rule of going down 1 card each time you mulligan (no scry), not the Commander mulligan of one free mulligan at the start, so the % chance of hitting your lands is actually a little higher for us
Perhaps youve already been in the scene for a while and are currently hunting for even rarer cards
Another direction to consider for Omniscience + Acererak combo is an infinite mana combo of Deadeye Navigator + Peregrine Drake which also can be repeatable venturing with any creature who ventures when it ETB since Deadeye can infinite blink it
And the sleeper of the whole ecosystem isn't in the set at all: the Pokemon Center-stamped Snorlax promo (SVP #051) from the PC ETB trades around $400 raw with PSA 10s over $2,100, roughly ten times its regular-ETB twin, the single most profitable packaging distinction in modern Pokemon
These effects do not appear outside of battles, even if you have them equipped