The main difference between a regular booster and a Jumpstart booster is that Jumpstart boosters are designed to be played out of the pack with just two of them and you dont need to do any deckbuilding at all, unlike other Limited formats where you still need to decide what to put in your deck
But these creatures should at least be considering for many such decks
6 Caesar, Legion's Emperor They're Disposable Attacking is all Caesar, Legion's Emperor, cares about and for good reason
On a result of 20, repeat this process
Their disruptions are the Traps as the Rituals don't have Quick Effects, but they too can break boards if you're going second etc
This one costs five mana instead of four and doesn't include a way to cast it for free, but if you're looking for a type manipulator in Black, this is one of your best options