There are ten mech lands, two for each basic land type: You can find the mech basic lands in traditional foil and non-foil in The Brothers' War Set and Draft Boosters
Getting both pieces in hand can be taxing, so if you have Brash Taunter or another indestructible creature on board, using Sunforger to find the other piece can be a massive help
It is a very odd mana rock, because you are spending mana to get 1 less than you spent, but I think the threat here is that it then also becomes an 8/8 that makes opponents start sacrificing permanents, which seems pretty strong, especially since it is safe from creature-based removal until you turn it on
Lastly, theres this new Saga card, which is seemingly another all-star in value
I loved this card in Standard while it was legal, and its even recently made it into some of my casual control Commander decks