Think about cards like Krenko, Mob Boss, where you want to make as many goblins with that ability as possible, and Marvin can do it too
While that's a hearty chunk of rules text for a card, Witness of the Ancient is effectively a bridge to summoning powerful monsters much sooner in matches
Planeswalkers (4) Lands (24) Spells (32) It was quite the surprise to see him playing for Top 8 on camera against Jon Stern in Round 15
Lrien Revealed Three cards for five mana is an acceptable rate, if not particularly exciting
Cards with first strike, haste, or the ability to growlike Monastery Swiftspeartend to dominate because they win trades and hit fast
I am grouping each of these together, since they are pretty similar in role