The best steer we have is that Wizards now tries to place bans in the first few weeks after a new set releases - so checking the release dates can provide a good guide
Enterprise-D, Galaxy-Class Crystalline Entity Watery Grave Temple Garden Stomping Ground Steam Vents Sacred Foundry Overgrown Tomb Hallowed Fountain Godless Shrine Breeding Pool Blood Crypt
To put it into perspective, there are 118 unique cards that reference "power four or greater," 10 that reference power six, and 16 that reference power eight
Belle's House can be played fairly early as well, helping you establish the groundwork for building a powerful combination of characters and items
Kwain, Itinerant Meddler Kwain, Itinerant Meddler is nice because it gives every player more resources
It is incredibly well balanced, without the two life it would just be the Lightning Bolt of the discard spells with no reason ever not to pick and play it first