28 cards where the block is “ons” and the card types include “enchantment” and the mana value <= 2

Cover of Darkness (Onslaught #133)
Crown of Ascension (Onslaught #78)
Crown of Awe (Onslaught #16)
Crown of Fury (Onslaught #196)
Crown of Suspicion (Onslaught #134)
Crown of Vigor (Onslaught #253)
Custody Battle (Onslaught #197)
Dragon Breath (Scourge #86)
Dragon Fangs (Scourge #117)
Dragon Scales (Scourge #10)
Dragon Shadow (Scourge #65)
Dragon Wings (Scourge #34)
Fatal Mutation (Scourge #66)
Guilty Conscience (Scourge #17)
Invigorating Boon (Onslaught #267)
Lavamancer's Skill (Onslaught #215)
Lightning Rift (Onslaught #217)
Lingering Death (Scourge #69)
Mistform Mask (Onslaught #94)
One with Nature (Scourge #125)
Oversold Cemetery (Onslaught #160)
Pacifism (Onslaught #47)
Pyrostatic Pillar (Scourge #100)
Sea's Claim (Onslaught #113)
Shared Triumph (Onslaught #53)
Steely Resolve (Onslaught #286)
Uncontrolled Infestation (Scourge #108)
Withering Hex (Onslaught #181)

This search is finished. Now the real work can begin.