This build WANTS Oketra and is constructed to take advantage of her abilities as a nearly-impossible-to-remove house that makes Super-Big-Gulp-sized zombies to run over the endgame
If you sink enough mana into its X cost, your opponents will either die or have no resources left to defend themselves, both on the battlefield and in their hand
If you draw a low-cost sliver and have a lot of mana spare, plugging it all into this effect can give you a load of bodies, ready to receive whatever buff your other slivers can provide them
Her +1 creates two temporary 3/1 Elemental tokens with Haste that can pressure opponents, take down vulnerable Planeswalkers, or feed sacrifice outlets before they disappear
It shuts down spellslinger strategies harder, as they often want to leverage at least a few expensive spells
The Metamorph can literally go in any deck although blue is its favourite home as casting is more flexible and artifact synergy is highest