There must be four or more card types among cards in your graveyard in order for these abilities to trigger
Cards that take too much damage are banished, though any damage sustained during a challenge remains until a card effect removes it
In terms of other pricey cards that arent as notable, youre looking at Calculating Lich, Seasoned Dungeoneer, and Grim Hireling which all float around the $10 range
Your commander counts as one of those 100 cards, and they start the game in the Command Zone rather than in the deck
Azula, Cunning Usurper This fun Dimir version of Azula at 4/4 size and five mana is next
Human decks that go beyond Boros or Selesyna are usually in blue (if not all colors), and dont tend to struggle for card draw