Look for certain telltale signs such as: Poor card quality
Throughout Ergamon's wild Truga Jungle, predator-prey relationships stopped until every last invader was crushed to dust
A 3/4 flier for four mana that mills 3 cards on attack feels more like a draft card than the face of a Commander product, even if you do get to keep an artifact creature or vehicle from among those cards
Still, this kind of library manipulation at this low of an opportunity cost is just too much, so I would not be surprised at all to eventually see it banned in Modern, as it already is in Pioneer and Standard
If the Vanguard format were to see a modern resurgence, I suspect these would spike in price
Soul Warden is a classic life gain card, rewarding you for every creature you play