Because flashback could only go on instants and sorceries, many of the green cards in the set with flashback generate creature tokens, creating something akin to creature spells with flashback
Fans have seen some of these cards arrive in Chapter One with a couple of versions of Dr
Inuarashi 9-cost is a late-game win condition, capable of going for 3 attacks in one turn
Witherbloom Pestilence (Black/Green) Strategic sacrifices, life gain and drain Dina, Essence Brewer sacrifices creatures for card draw, but can also sacrifice other creatures to power up another card and gain more life
[1] Technically, there are ways to "refresh" the timestamp of a permanent, so the order they entered the battlefield is not always the same as their timestamp order, but none of those ways applies in the situation as described.