"Mothra's Giant Cocoon", "Battra, Dark Destruction Beast", and "Mechagodzilla, Battle Weapon" will only be printed in Japanese
Faceless Haven This may be no Mutavault in terms of power, but its not a terrible replacement for it either
If you've never seen Nadu in action, its ability (revealing the top card of your library whenever one of your creatures becomes a target of a spell or ability, then putting it into play untapped if it's a land or putting it into your hand if it's not, twice each turn for each creature) creates not infinite but sort of functionally infinite loops with an equipment that equips for free, like Skullclamp or Lightning Greaves
Rad counters mill players slowly and drain their life totals, and feel like the perfect complement to a +1/+1 counter strategy, since youll be pressuring life totals and proliferating everything in sight
And just like a normal saga, they'll sacrifice themselves as the final chapter ability resolves