This means that if they are too good, like Nexus of Fate, the promo nature of the card will limit its supply and make it more difficult to acquire and play with
Detective's Phoenix Hailing from Modern Horizons 3, Detective's Phoenix combines a few interesting mechanics together, using bestow and collect evidence to put a unique spin on a Phoenix creature
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But what the card does do is make your deck operate more consistently, allowing you to play lands from the top of your deck, and dodge the dissatisfaction of a late land draw
It can get out of hand quickly and so should be dealt with quickly if youre on the other side of the table
That said, you should definitely put them in a sleeve whenever you find one