Damage Soak is nice, especially in lower levels and if you actually DO give infinite cantrips.
The Bone spells can be fun in lower levels when going against goblins and kobolds (or later by making an army of skeleton chickens)
Switcheroo: watch your players set up shell games.
Really Cantrippin': better any random effects? using a 3rd spell slot gets you a +6 to all saves via resistance.
Especially ones with many effects: take a 3rd spell slot (new variables in brackets)
up to 4 (24) spheres of light in a 10'(not an effect) area give off 30' (180') light. They can move 100' (600') per round.
Though allowing something like that would definately have your characters using cantrips all the time.