Flash
When Security Initiative enters, you may tap or untap target nonland permanent. Then draw a card.
An opponent controls three or more tapped nonland permanents.

Destroy target artifact.

Enchant creature
Enchanted creature gets -3/-0.

Serpentine Woods enters tapped.
{T}: Add {B} or {G}.
{2}{B}{G}, {T}, Sacrifice Serpentine Woods: Draw a card.

{B}, Sacrifice Serrated Fossil: Choose a nonland card name. Target player reveals their hand and discards a card with that name if able. Activate only as a sorcery.
Surface {3}{B}{B}. Serrated Fossil surfaces transformed.

Whenever a nontoken creature you control dies, create a token that's a copy of it, except it's a Minion and has decayed.

Set Ablaze deals 2 damage to any target. You may discard up to two cards, then draw that many cards.

At the beginning of your end step, put a +1/+1 counter on each tapped creature you control.
{G}{W}{U}, Remove five counters from among creatures you control, Sacrifice Severin's Masterwork: Create Chaneryx, Perfect Lifeform, a legendary 10/10 green, white, and blue Leviathan creature token with ward {10}.

You may remove +1/+1 counters from creatures you control as though they were loyalty counters on Severin, Sparkmind to pay its loyalty costs.
[0]: Create a 0/0 colorless Robot artifact creature token with two +1/+1 counters on it.
[–2]: You may tap or untap each of up to three target permanents.
[–7]: If it isn't an extra turn, take an extra turn after this one.

When Shadow Sky enters and whenever you cast a spell, each creature target player controls gets -1/-1 until end of turn.

Until end of turn, target creature you control gets +1/+1 for each different creature type among non-Coward creatures you control. All creatures able to block it this turn do so.

Put a +1/+1 counter on target creature. It gains trample until end of turn.

Enchant creature you control
When Shatter the Reflection enters, you may destroy target artifact or enchantment.
Enchanted creature gets +1/+0 and has deathtouch.

Shell Cove enters tapped.
{T}: Add {G} or {U}.
{9}{G/U}: Shell Cove becomes a 7/7 green and blue Leviathan creature with ward {3} until end of turn. It's still a land. This ability costs {X} less to activate, where X is your devotion to green and blue. Activate only once each turn.

Time loop
I — Create a tapped Treasure token.
II — You may discard a card. If you do, exile the top two cards of your library. You may play one of those cards this turn.
III — This Saga deals 2 damage to each opponent.

Draw cards equal to the greatest power among creatures you control. At the beginning of the next end step, discard that many cards.

Shock deals 2 damage to any target.

Equipped creature can't be blocked by creatures with power 2 or less.
Whenever equipped creature attacks, it gets +X/+X until end of turn, where X is its power.
Equip {3}

At the beginning of combat on your turn, you gain 1 life. If you control three or more Shrines, instead you gain 3 life.

At the beginning of combat on your turn, you may tap target nonland permanent. If you control three or more Shrines, put a stun counter on it.

{4}{B}: You draw a card and you lose 1 life. This ability costs {1} less to activate for each other Shrine you control. Activate only once each turn.

At the beginning of your upkeep, create a 1/1 white Human creature token for each Shrine you control.

At the beginning of combat on your turn, target creature or Shrine you control gains first strike until end of turn. If you control three or more Shrines, it gains double strike until end of turn instead.

At the beginning of combat on your turn, creatures you control get +1/+1 until end of turn. If you control three or more Shrines, they get +2/+1 until end of turn instead.

At the beginning of combat on your turn, you may discard a card. If you do, scry 2 if you control three or more Shrines, then draw a card.