The first spell you cast during each of your opponent's turns cost {U}{B} less to cast.
During each ending phase, nonland cards in your graveyard have flash and surface. The surface cost is equal to their mana cost.
Surface {6}{U}{U}{B}

When Iris Cultist enters, you lose 1 life.
Cybersoul {4}{B}

Flash
When Hazakh Ambassador enters, target creature gains deathtouch until end of turn.
Basic landcycling {1}{B}

Hundred-Handed Pillars enters tapped.
{T}: Add {W} or {U}.
{7}{W/U}: Hundred-Handed Pillars becomes a 4/6 white and blue Giant creature with vigilance until end of turn. It's still a land. This ability costs {X} less to activate, where X is your devotion to white and blue. Activate only once each turn.

{1}, Sacrifice Traveler's Amulet: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Ninjutsu {2}{G}{U}
Whenever this creature deals combat damage to a player, you may search your library for a land card, put it onto the battlefield tapped, then shuffle. That land becomes a 4/4 Dragon creature in addition to its other types.

The owner of up to one target nonland permanent puts it on the top or bottom of their library. Return each other nonland permanent to its owner's hand.

When Ace Tamer enters, look at the top six cards of your library. You may reveal a non-Human creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Flash
This spell costs {X} less to cast, where X is the number of Plains you control plus the number of cards with a cycling ability in your graveyard.
When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.
Plainscycling {2}

Whenever you gain control of a permanent you don't own or a permanent you don't own enters under your control, put a +1/+1 counter on Vagrant Sorceress.

Choose up to X, where X is one plus the number of creatures you control with level counters on them.
• Each opponent discards two cards.
• Creatures your opponents control get -1/-1 until end of turn.
• Each opponent loses 3 life and you gain 3 life.

This spell costs {X} less to cast, where X is the amount of mana you've spent to activate abilities this turn.
Exile target nonland permanent.

Trample
Landfall — Whenever a land you control enters, target creature blocks Brick Breaker this turn if able.

Titan's Stairs enters tapped.
{T}: Add {R} or {W}.
{3}{R/W}: Titan's Stairs becomes a 2/2 red and white Archon creature with flying until end of turn. It's still a land. This ability costs {X} less to activate, where X is your devotion to red and white. Activate only once each turn.

At the beginning of your end step, if you control two or more other enchantments, create a 1/1 white Human creature token.

Frigid Highlands enters tapped unless you control an Island.
{T}: Add {R} or {G}.

At the beginning of your end step, you gain 1 life. Then if it's your first turn of the game or you discarded a card named Leystone of Being this turn, create an X/X white Avatar creature token, where X is the difference between your life total and your starting life total.
Cycling {W}

Whenever Zakros Decree or another enchantment you control enters, target creature you control gets +1/+1 and gains lifelink until end of turn.

This spell costs {1} less to cast if there is a card named Avert Disaster or Imminent Disaster in your graveyard.
Exile target creature or planeswalker.

Flying, lifelink, haste
This creature can't block.
When this creature enters, if it was cast, create a red and white Subroutine enchantment token named OVERFLOW with “Whenever this Subroutine runs, return a card named Offset Daemon from your graveyard to the battlefield.”

Whenever Skotha enters or attacks, each opponent discards a card. Then you may return a permanent card with mana value 3 or less from your graveyard to the battlefield.
{B}{B}{G}{G}: Return Skotha from your graveyard to the battlefield, then put it on the bottom of its owner's library. Activate only as a sorcery.

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U}

Create a token that's a copy of target creature, except it's 3/3.

Whenever this creature attacks, if you control another tapped creature, this creature gains first strike until end of turn.

{1}, Sacrifice Claw Fossil: Target creature has base toughness 1 until end of turn. Activate only as a sorcery.
Surface {2}{B}. Claw Fossil surfaces transformed.