There are a lot of fantastic hits you can get off of Ellie and Alan, potentially casting a giant spell without ever spending mana to actually cast it (just the mana used to cycle the creature in the first place)
Trollbred Guardian Trollbred Guardian has +1/+1 counter synergies that let it grow on its own and give trample to your other creatures with counters
That remains to be seen, but those of us who enjoy the format will find at least one deck to gravitate towards, and those of us that have a tendency to collect a few at a time will be well satiated
Not just under your control
Mulldrifter - a value staple of Commander for quite some time, this five-mana 2/2 flier also has evoke for three mana, allowing to to enter and trigger its ability to draw two cards before sacrificing it
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