Offering some cross-tribal benefits for assassins, mercenaries, and rogues, Mari seems like an excellent support card for Etrata, the Silencer due to her ability to exile enemy creatures with hit counters on them when they die
Throw in that surprisingly solid parting shot death trigger, and Moonveil Regent punches well above its financial weight in 2026
When it enters, it picks an enemy creature and everything else gets -2/-2 to set up a one-on-one showdown
Four power is utterly huge
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of Urianger Augurelt's last ability)
So although there were roughly 277K (again, this is my rough estimate) Revised Booster Boxes made, over the years that number has dwindled down as more and more got ripped open