This is important, as whenever Nethroi mutates, its controller can return any number of creature cards with total power 10 or less from their graveyard directly to the battlefield.This can bring back a massive board state from the graveyard with the effect of a single card, potentially swinging the game in its controller's favor
Unfortunately, the options are limited in Standard thanks to the banning of Felidar Guardian (which would be pretty absurd in a Saga deck), but Release to the Wind can get the job done in a pinch
It takes too much setup for my liking, but with the right amount of support it could do some work

Warhammer 40,000 Commander Ghyrson Starn, Kelermorph 19,842decks Marneus Calgar 16,900decks Be'lakor, the Dark Master 15,287decks Magus Lucea Kane 14,818decks Imotekh the Stormlord 7,992decks Abaddon the Despoiler 6,542decks Magnus the Red 5,905decks The Swarmlord 3,012decks Inquisitor Greyfax 2,569decks Trazyn the Infinite 2,407decks Commissar Severina Raine 2,321decks Khrn the Betrayer 2,007decks Celestine, the Living Saint 1,969decks Mortarion, Daemon Primarch 1,786decks Szarekh, the Silent King 1,609decks Belisarius Cawl 1,374decks Inquisitor Eisenhorn 1,187decks Anrakyr the Traveller 1,004decks Lucius the Eternal 987decks Deathleaper, Terror Weapon 834decks Neyam Shai Murad 623decks The Red Terror 614decks Illuminor Szeras 584decks Old One Eye 371decks Commanders (Reprints) Cards Sceptre of Eternal Glory 0.7%inclusion 67K decks 9.55M decks Bloodthirster 1.3%inclusion 60.8K decks 4.75M decks Cryptothrall 0.6%inclusion 56.5K decks 9.55M decks Biophagus 1.2%inclusion 53.7K decks 4.40M decks Celestine, the Living Saint 1.2%inclusion 52.8K decks 4.43M decks Reaver Titan 0.5%inclusion 51.7K decks 9.55M decks Exalted Flamer of Tzeentch 2.2%inclusion 50.5K decks 2.25M decks Keeper of Secrets 1.0%inclusion 48.7K decks 4.75M decks Canoptek Spyder 0.5%inclusion 48.2K decks 9.55M decks Out of the Tombs 1.0%inclusion 47.3K decks 4.85M decks Blood for the Blood God

We should have been better, we can be better, and we will be better. The affected cards are Invoke Prejudice, Cleanse, Stone-Throwing Devils, Pradesh Gypsies, Jihad, Imprison, and Crusade