Here, the answer is pretty simple: the most valuable cards from an Un-set are the least valuable cards from a normal set: the basic lands and tokens
Use a small flashlight to see if it shines through the card
The controller of each Warrior token created by Najeela chooses which player or planeswalker it's attacking
SA cards pull at roughly 1 per 4 boxes total, distributed across all SA variants in the set (Mew VMAX SA, Mew V SA, Genesect V SA, Greedent V SA)
It may not be as flashy or exciting as ex decks (although that full art Weezing art is lovely), but its great fun
Many white cards provide value in different ways, like God-Eternal Oketra or Teshar, Ancestors Apostles cast triggers, though we wont be talking about them here today as they dont result in more physical cards being drawn