Every green deck in any format will want this card. Strictly better than forest but also multiples are completely fine so 3 is probably the right number to play. Only bad thing is unfetchable.

Oh also it says 'with a basic land type' which allows opponents to grab shocklands or OG duels, wizards definitely made this with eternal formats in mind, we'll see if it is played.

Assassin's Trophy has seen play before, and while this is narrower, it can also be a land, can also be channeled as an instant, can cost with another Legendary (like Thalia, Guardian of Thraben), and, as an activated ability, it can't be countered outside of Stifle effects.

I think every green deck in Legacy, Modern, and Pioneer, particularly Maverick lists with Thalia and Gaddock Teeg would run at least 1 main and possibly side some for Tron/Post and maybe Lantern Prison if it still exists somewhere.