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
Plant/Pendulum/Effect
The game has seen many changes over the years and it is an awful lot different now compared to when it was released
I can't more strenuously recommend Bant (or at least, not Sultai )
No matter what cards were designed for them, with The Ur-Dragon and O-Kagiachi headlining the same deck side-by-side, one of them was going to feel underwhelming, and its definitely O-Kagiachi
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