msem-instigator

When Atlas of Worlds enters the battlefield, search your library for any number of land cards with different names and exile them, then shuffle.
You may play lands exiled with Atlas of Worlds.

Converge — Counter target spell unless its controller pays {1} for each color of mana spent to cast Cosmic Sinkhole.

Choose two —
• Destroy target artifact.
• Discard a card, then draw a card.
• Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Journey three times. (Exile the top three cards of your library face up. Whenever a creature you control deals combat damage to an opponent, put a journeyed card you own into your hand.)

Search your library for a Plains, Island, Swamp, or Mountain card and put it onto the battlefield tapped, then shuffle.

Each player mills three cards.
Draw a card.

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Create a tapped colorless Mountain Forest land token. (It has “{T}: Add {R} or {G}.”)

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.