The sixth and seventh are single-faced uncommons
If your deck does not have access to green, you might have to get more creative by using cards like Tithe, Pilgrims Eye, or even Demonic Tutor to put lands into your hand, cards like Mana Geyser, High Tide, or Caged Sun to get a big payoff, or mana rocks like Arcane Signet, Coalition Relic, and the Ravnica Signet cycle (Boros Signet, Izzet Signet, etc.) to speed things along at the risk of seeing them destroyed later
Collector Boosters may contain these cards: FDN 1271, 282487
I recommend selling these second because you still will have some energy left after selling your foils wont have eBay fatigue yet
Explorers of the Deep will likely live up to that legacy, with +1/+1 counters and ramp allowing Simic colors to do what they do best