Having access to Arcbound Ravager and Steel Overseer while still easily coming in under budget is a huge, huge boost of power for a budget Affinity deck
This set includes the Umbreon VMAX (Alt Art) and Rayquaza VMAX (Alt Art) cards, which are currently two of the top three most expensive Sword and Shield cards.
Slagstorm deals 3 damage to each creature on the battlefield for only three mana (or it can deal the last 3 damage to your opponent in a pinch)
For reprints, Strionic Resonator, Swiftfoot Boots, and all three on-color Signets are notable
For Strixhaven, the Silverquill theme booster is an excellent choice as the faction itself is white/black with several lifelink creatures
I'm sure not many players have even heard of Taniwha or Shimmer, let alone have desire to cast such cards