If the card is a tutor target only for a specific matchup or scenario, such as Giver of Runes with Ranger-Captain of Eos out of Mardu Deaths Shadow, then one copy is always correct
This pairs particularly well with certain key partners, such as Akiri, Line Slinger or Anara, Wolvid Familiar, both of whom make it very difficult for your opponents to stop your attacks profitably
Because of that, you can buy the red and green theme boosters to get some fight cards reliably
Legions Landing will also be the backbone of any Vampire aggressive deck, as its the perfect payoff for generating plenty of small tokens, but its not only useful in Vampire decks
All somewhat rough choices however the only totally incorrect one is the one without the life gain
Blue Delightful Discovery Were kicking things off with the color of card draw, blue