15 cards where it’s legal in Future Standard and the text includes “mill” and the color identity ≥ U and the mana value < 3

Coral Colony (Dominaria United #45)
Cruel Somnophage // Can't Wake Up (Wilds of Eldraine #222)
Disturbing Conversion (March of the Machine #54)
Fallaji Archaeologist (The Brothers' War #48)
Font of Progress (Phyrexia: All Will Be One #51)
Founding the Third Path (Dominaria United #50)
Inverted Iceberg // Iceberg Titan (The Lost Caverns of Ixalan #60)
Inverted Iceberg // Iceberg Titan (The Lost Caverns of Ixalan #60)
Nashi, Searcher in the Dark (Duskmourn: House of Horror #223)
Picklock Prankster // Free the Fae (Wilds of Eldraine #64)
Restless Reef (The Lost Caverns of Ixalan #282)
Scrabbling Skullcrab (Duskmourn: House of Horror #71)
Song of Stupefaction (The Lost Caverns of Ixalan #77)
The Ancient One (The Lost Caverns of Ixalan #222)
Urborg Lhurgoyf (Dominaria United #186)
Waterlogged Hulk // Watertight Gondola (The Lost Caverns of Ixalan #83)
Waterlogged Hulk // Watertight Gondola (The Lost Caverns of Ixalan #83)

It is the moment of discovery, the triumph of the mind, and the end of these results.