Zygon Infiltrator

Body-print — {2}{U}: Tap another target creature and put a stun counter on it. Zygon Infiltrator becomes a copy of that creature for as long as that creature remains tapped. Activate only as a sorcery. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Iraxxa, Empress of Mars

Trample
Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Paradox — Whenever you cast a spell from anywhere other than your hand, create a 2/2 red Alien Warrior creature token.

Memory Worm

Paradox — Whenever you cast a spell from anywhere other than your hand, Memory Worm deals 2 damage to target player. That player discards a card, then draws a card. Put a +1/+1 counter on Memory Worm.

Sycorax Commander

First strike, haste
Sanctified Rules of Combat — When Sycorax Commander enters, each opponent faces a villainous choice — That opponent discards all the cards in their hand, then draws that many cards minus one, or Sycorax Commander deals damage to that player equal to the number of cards in their hand.

Weeping Angel

Flash
First strike, vigilance
Whenever an opponent casts a creature spell, Weeping Angel isn't a creature until end of turn.
If Weeping Angel would deal combat damage to a creature, prevent that damage and that creature's owner shuffles it into their library.

Vashta Nerada

Indestructible
Shadow (This creature can block or be blocked by only creatures with shadow.)
Morbid — At the beginning of each end step, if a creature died this turn, put a +1/+1 counter on Vashta Nerada.

The Eleventh Hour

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Search your library for a Doctor card, reveal it, put it into your hand, then shuffle.
II — Create a Food token and a 1/1 white Human creature token with "Doctor spells you cast cost {1} less to cast."
III — Create a token that's a copy of target creature, except it's a legendary Alien named Prisoner Zero.

Auton Soldier

You may have Auton Soldier enter as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Davros, Dalek Creator

Menace
At the beginning of your end step, create a 3/3 black Dalek artifact creature token with menace if an opponent lost 3 or more life this turn. Then each opponent who lost 3 or more life this turn faces a villainous choice — You draw a card, or that player discards a card.