Laying out The Thief & the Necromancer this past weekend, I found that in The Thief I had 3 blank pages at the end of the zine (like you do). I decided to add a few new unlockable stage magic sleights: "the Invisible Bird," "the Lively Doll," and "the Singing Jar."
In the crowded and highly competitive field of ttrpg rules for stage magic, I'll put this game up against the best you've got.