Windswept Heath doesn't actually have the green mana symbol on it, it simply says search your library for a
plains or
forest. In this case I'm using the
plains part of that to fetch
Sacred Foundry or
Plateau as comes into play untapped dual lands. In addition due to the importance of
Mistveil Plains when I have
Sunforger, it lets me grab it due to its
plains type. At worst the fetchlands are basic
plains that cost 1 life, but they are definitely legal.