Anything inefficient or redundant can be let go, and to me this includes most of the combat-focused cards
DESCRIPTION: Kaladesh (first glimpsed in Magic Origins as the birthplane of Chandra Nalaar) is a plane where natural mages are rare
If you cast a spell for another cost "rather than pay its mana cost", you can't choose to cast it for any alternative costs
We also have an entire ranking dedicated to card draw payoffs if you're interested in more depth on the subject
Whenever a land enters the battlefield under its owner's control, Bloodghast's controller may return it from their graveyard to the battlefield, meaning even if it is destroyed, it will likely be back soon
The reason From Beyond traded so cheaply before the new Eldrazi Modern Horizons 3 commanders released, was that no previous Eldrazi commander could run the card in its deck