Like most Magic: The Gathering cards, the value of Millikin depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy Commander)
In addition to your normal need for flashback cards, if you're trying to fly to victory with Delver of Secrets, then you're going to need a good number of instants and sorceries so they can turn into Insectile Aberrations
This is especially good because they both get way better the more of them are in play though you do have to choose to go with one or the other to maximize their potential
Shuffling a creature away is usually in white's or blue's wheelhouse, with red being able to replace it with a different card
This involves printing a out the reference image to scale, applying graphite to the back of the print, laying the print over the card, and then, tracing the art on the print
Galvanic Bombardment R Instant Galvanic Bombardment deals X damage to target creature, where X is 2 plus the number of cards named Galvanic Bombardment in your graveyard