Wondrous Item, uncommon (requires attunement by a spellcaster)
These cobalt and steel chainmail wristguards have blue shield patterns on the back of the hand. While wearing the wristguards, whenever you cast an Abjuration cantrip, you can use a bonus action on the same turn to cast that cantrip a second time.
Notes: spellcaster
Unless you have some home brew cantrips 3 of the 4 abjuration cantrips have durations of concentration and the other one only targets self.