Search Ebay for "2018 Zobrist Peek" now and you'll find just one listed and three more that have sold. While I bought mine on Ebay, it is not one of the four.
The seller didn't do a very good job of listing the card. Zobrist's name wasn't in the auction title. Thanks to that omission, there were not many eyeballs on the auction and I was able to get the card for half the price of what the others are going for.
There is one more SSSSP out there, a Kris Bryant Stadium Signatures card. It's odds are slightly better, at 1:1572 packs, but because its Bryant, the prices are higher. The sold ones on Ebay went for at least $50. I don't think I'll run across a deal on that one.
So that should wrap up Opening Day for me.... 18 Cubs cards.