For my money, Animated Army is probably the Bloomburrow precon that has a strategy best suited to competitive play
With some tools like Crucible of Worlds, you get to do it every turn
So I leaned into being an Archenemy with a full-blown board control deck that knocks players out with 3 hits from my Slurm Queen, group slug () damage effects, or proliferate shenanigans
Otherwise, Black Skull Dragon functions well enough by itself to be worthwhile in most scenarios.
If you are foiling out a Commander deck, chasing a specific borderless mythic, or collecting every variant of a set, collector boosters concentrate those premium cards in a way that play boosters simply cannot match
Nature's Will can technically do it too, but it untaps lands after damage, which is too late for Hellkites trigger unless you already have an extra combat to set it up