Marketplaces like eBay are a great starting point since they have a massive volume of listings, which gives you a solid baseline for a card's current market value
Any "as [this creature] enters" or "[this creature] enters with" abilities of the copied creature will also work.
Just behind your life total and mana, having a well-stocked graveyard can enable all sorts of mechanics and deck strategies, provided you know how
If the rest of the Eeveelutions move toward that mark, expect Roaring Moon to soar past some of them
Note that the new Eldrazi titans are worded to be less tempting to copy with this, so let that inform you of its power
The destruction of persistence, including the land, is the core, which is used for the use of the lamp deck as soon as possible and copying or blinking