mtg explorers of the deep card list What are best cards to upgrade the with 10 double Explorers of the Deep Upgrade

No need to talk about each piece, but there are a couple worth mentioning specifically

Quantum Riddler This is likely my favorite card in the set

Red is meant to be a proactive color, but the problem is that making waves is heavily discouraged in a format with three opponents

Just paying 4 mana to copy the strongest token around (populate, if you will) is very good, and lots of cards and commanders can give you a token every turn, meaning that this class will draw you a bunch of cards even on your opponents turns

Getting to draw cards and create Treasures is great, but not at the expense of losing this creature that you already spent your mana on