Producing mana, attacking, and activating certain abilities require tapping a card, turning it sideways to indicate it has been used
The effect doesn't trigger only once either, allowing for each artifact or enchantment you cast to build up more value
Card Set(s) -ROYAL BLOOD- [OP-10] CARD VIEW OP10-071 | SR | CHARACTER Donquixote Doflamingo Attribute Special Block icon 3 Type The Seven Warlords of the Sea/Donquixote Pirates Effect [On Play] DON
You can see why this is on my Top Ten list, but just outside in my Honorable Mention section
When it is a benefit to your tribe that cannot easily be interacted with by the rest of the table and in the case of Edgar, does not cost you mana, it becomes something that leaves a reasonably sour taste in the mouths of the player base
Add deeper layers of intrigue to your next Magic draft and begin plotting as soon as you open your first booster pack