Whenever a Forest enters the battlefield under your control, create a 5/3 green Elemental creature token
Be free to break those rules and differentiate as you see fit, as many times special builds/decks require quite different approach and it heavily depends on your preferred playstyle, the chosen commander and the mechanics in use, among other things as well
Like Pokmon Go, that selection will expand over time, and I expect Ill get tired of it eventually
The description doesn't tell you that you're locked to certain cards and unable to build fully custom decks from outside the set cards
Much like the Artifact, Beseech the Mirror is playable in multiple MTG formats that range from Standard and Pioneer to Commander and Vintage
If we ever get Dakmor Salvage on Arena, this could be a sweet little dredge engine