There are several really exciting new lands in War of the Spark, and it looks like Karn's Bastion is going to go into all Proliferate-based decks in Standard.
It's not just a land, which comes into play untapped, it's also a repeatable spell/utility that can make all your creatures and planeswalkers grow every turn.
The two best archetypes for Karn's Bastion are Green-White Tokens and Abzan Superfriends. The first one will use the Bastion for growing creatures/tokens, and the second one is focused around keeping planeswalkers alive and exploiting their powerful minus abilities.
Also, if you have additional tools to untap your lands at your end steps, such as Wilderness Reclamation, then you could use the Proliferate ability twice a turn.