24 cards where the set is “mps” and (the collector number >= 31 and the collector number <= 54)

Arcbound Ravager (Kaladesh Inventions #31)
Black Vise (Kaladesh Inventions #32)
Chalice of the Void (Kaladesh Inventions #33)
Defense Grid (Kaladesh Inventions #34)
Duplicant (Kaladesh Inventions #35)
Engineered Explosives (Kaladesh Inventions #36)
Ensnaring Bridge (Kaladesh Inventions #37)
Extraplanar Lens (Kaladesh Inventions #38)
Grindstone (Kaladesh Inventions #39)
Meekstone (Kaladesh Inventions #40)
Oblivion Stone (Kaladesh Inventions #41)
Ornithopter (Kaladesh Inventions #42)
Paradox Engine (Kaladesh Inventions #43)
Pithing Needle (Kaladesh Inventions #44)
Planar Bridge (Kaladesh Inventions #45)
Platinum Angel (Kaladesh Inventions #46)
Sphere of Resistance (Kaladesh Inventions #47)
Staff of Domination (Kaladesh Inventions #48)
Sundering Titan (Kaladesh Inventions #49)
Sword of Body and Mind (Kaladesh Inventions #50)
Sword of War and Peace (Kaladesh Inventions #51)
Trinisphere (Kaladesh Inventions #52)
Vedalken Shackles (Kaladesh Inventions #53)
Wurmcoil Engine (Kaladesh Inventions #54)

The message was clear to Sorin—time to search for something else.