The Eldest Reborn

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent sacrifices a creature or planeswalker of their choice.
II — Each opponent discards a card.
III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.

Kasmina, Enigmatic Mentor

Spells your opponents cast that target a creature or planeswalker you control cost {2} more to cast.
−2: Create a 2/2 blue Wizard creature token. Draw a card, then discard a card.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Sol Ring

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Nicol Bolas, Dragon-God

Nicol Bolas, Dragon-God has all loyalty abilities of all other planeswalkers on the battlefield.
+1: You draw a card. Each opponent exiles a card from their hand or a permanent they control.
−3: Destroy target creature or planeswalker.
−8: Each opponent who doesn't control a legendary creature or planeswalker loses the game.

Counterspell

Mountain

Professor Onyx

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life.
+1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
−3: Each opponent sacrifices a creature with the greatest power among creatures that player controls.
−8: Each opponent may discard a card. If they don't, they lose 3 life. Repeat this process six more times.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth, Spider Queen.
0: You draw a card and you lose 1 life.
−3: Create two 2/1 black Spider creature tokens with menace and reach.
−8: You get an emblem with "Whenever an opponent is dealt combat damage by one or more creatures you control, if that player lost less than 8 life this turn, they lose life equal to the difference."

Jace, Arcane Strategist

Whenever you draw your second card each turn, put a +1/+1 counter on target creature you control.
+1: Draw a card.
−7: Creatures you control can't be blocked this turn.

Dimir Signet

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures of their choice.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Nicol Bolas, the Arisen

+2: Draw two cards.
−3: Nicol Bolas, the Arisen deals 10 damage to target creature or planeswalker.
−4: Put target creature or planeswalker card from a graveyard onto the battlefield under your control.
−12: Exile all but the bottom card of target player's library.

Nicol Bolas, the Ravager

Flying
When Nicol Bolas, the Ravager enters, each opponent discards a card.
{4}{U}{B}{R}: Exile Nicol Bolas, the Ravager, then return him to the battlefield transformed under his owner's control. Activate only as a sorcery.

Nicol Bolas, the Ravager // Nicol Bolas, the Arisen

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Island

Swamp

Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Arcane Signet

Lukka, Coppercoat Outcast

+1: Exile the top three cards of your library. Creature cards exiled this way gain "You may cast this card from exile as long as you control a Lukka planeswalker."
−2: Exile target creature you control, then reveal cards from the top of your library until you reveal a creature card with higher mana value. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
−7: Each creature you control deals damage equal to its power to each opponent.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Nicol Bolas, God-Pharaoh

+2: Target opponent exiles cards from the top of their library until they exile a nonland card. Until end of turn, you may cast that card without paying its mana cost.
+1: Each opponent exiles two cards from their hand.
−4: Nicol Bolas, God-Pharaoh deals 7 damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.
−12: Exile each nonland permanent your opponents control.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Karn, the Great Creator

Activated abilities of artifacts your opponents control can't be activated.
+1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.
−2: You may reveal an artifact card you own from outside the game or choose a face-up artifact card you own in exile. Put that card into your hand.

Narset, Parter of Veils

Each opponent can't draw more than one card each turn.
−2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.