Put two +1/+1 counters on each of X target lands you control. They each become 0/0 Elemental creatures with reach, haste, and "When this creature leaves the battlefield, conjure a card named Forest onto the battlefield tapped." They're still lands.

, Sacrifice a historic permanent: Seek a historic card.

At the beginning of your end step, choose a creature with the least toughness among creatures your opponents control. It perpetually gets -1/-1.
When your opponents control no creatures, sacrifice Penregon Besieged.

When Gixian Recycler dies or is put into your graveyard from your hand or library, conjure a card named Gixian Recycler into your graveyard.
Unearth

Flying
Whenever Yotian Courier attacks, choose one that wasn't chosen during your last combat —
• Create a tapped Powerstone token.
• Seek a nonland card with mana value equal to the number of Powerstones you control.

At the beginning of combat on your turn, choose one that wasn't chosen during your last combat —
• Up to one target Soldier perpetually gets +1/+1 and gains flying.
• Choose a Soldier card in your hand. It perpetually gets +1/+1 and gains vigilance.
• Create a 1/1 colorless Soldier artifact creature token.

Flying, haste
When Tomakul Phoenix dies, it perpetually gets +2/+2.
At the beginning of combat on your turn, you may pay , where X is Tomakul Phoenix's power. If you do, return it from your graveyard to the battlefield.

Starting intensity 1
Menace
At the beginning of your upkeep, sacrifice Great Desert Hellion unless you discard a card. If you discard a card this way, Great Desert Hellion intensifies by 1.
When Great Desert Hellion leaves the battlefield, you may discard your hand. If you do, draw cards equal to Great Desert Hellion's intensity.

When Urza's Construction Drone enters, conjure cards named Urza's Mine, Urza's Power Plant, and Urza's Tower into your library, then shuffle.
Whenever Urza's Construction Drone attacks or dies, seek an Urza's land card.

When Rusko, Clockmaker enters the battlefield, conjure a card named Midnight Clock onto the battlefield.
Whenever you cast a noncreature spell, put an hour counter on each permanent you control named Midnight Clock. Each opponent loses 1 life and you gain 1 life.

Creatures you control have trample.
Whenever one or more nontoken artifacts enter under your control, creatures you control perpetually get +1/+1.

Hexproof from white and from black
Whenever one or more Knights you control attack, draft a card from Raddic, Tal Zealot's spellbook.

Haste
When Fallaji Antiquarian enters, conjure a duplicate of another target nontoken creature or artifact you control into your graveyard. The duplicate perpetually gains unearth .

When Foundry Groundbreaker enters, sacrifice a land. Then conjure two cards named Mishra's Foundry onto the battlefield tapped.

Prototype — 3/3
When this creature enters, return target creature an opponent controls with power less than this creature's power to its owner's hand. If that creature wasn't a token, conjure a duplicate of it into your hand. It perpetually gains "You may spend mana as though it were mana of any color to cast this spell."