This spell costs {X} less to cast, where X is the amount of life you have more than your starting life total
Lifelink
When Rose Garden Guardian enters, put a +1/+1 counter on each other creature you control with lifelink.

When Rotroot Hauler enters, mill three cards, then you may put a permanent card in your graveyard on top of your library.

Vigilance
When Royal Templar enters, target creature gets +2/+0 and gains vigilance and indestructible until end of turn.
Cybersoul {3}{W}

Trample
Ruin, the First Shard enters with a +1/+1 counter on it for each mana spent to cast it.

Flashback costs you pay cost {2} less.
{R}, {T}, Discard a card: Draw a card.

Reach
{1}, Sacrifice a land: Put a +1/+1 counter on Runerock Automaton.

Runway Mech enters with a +1/+1 counter on it.

{VP}{VP}, Sacrifice another creature: Draw a card.

Instant and sorcery spells with mana value 4 or greater you cast cost {1} less to cast.
{U}{R}, Sacrifice Samacris: Return target instant or sorcery card from your graveyard to your hand. The next spell you cast this turn with the same name as that card costs {2} less to cast.

Flash
When Sanctum of the Two Truths enters, draw two cards.
Spellcharge 4

[+1]: Choose up to two target creatures. Until your next turn, when one of them leaves the battlefield, exile the other.
[0]: Reveal the top card of your library. You may reveal a card you own from outside the game that shares a mana value or card type with the revealed card. Put one of those cards into your hand and exile the rest.
[–7]: For each permanent on the battlefield, create a token that's a copy of it.

Sashanki, Destiny's Chosen can't be blocked alone except by multicolored creatures.
Whenever Sashanki, Destiny's Chosen attacks, another target creature you control gets +X/+X until end of turn, where X is Sashanki's power.

Prowess
When Satyr Arsonist enters, destroy up to one target nonbasic land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Hexproof from permanents

Whenever you cast an instant or sorcery spell, choose one that hasn't been chosen this turn —
• Create a 1/1 colorless Construct artifact creature token.
• Discard a card, then draw a card.
• Add one mana of any type.

{1}{R}, {T}, Discard a card: Draw a card. Scalding Crucible deals 1 damage to each opponent.
Spellcharge 5

Players can't gain life.
Whenever a player casts a spell, Scathing Remarks deals 1 damage to that player for each of that spell's colors.

This spell can't be countered.
Players can't gain life.
{1}{R}: Scorching Condemnation becomes a 4/4 red Elemental creature with trample and haste until end of turn. Activate only during your turn.

{3}, {T}, Sacrifice Scorching Illuminator: Return target instant or sorcery card from your graveyard to your hand. Add one mana of any color.

Trample
When Scourge of Capitalism enters, it fights target creature with the greatest power or tied for the greatest power among creatures you don't control. Excess damage is dealt to that creature's controller instead.

Haste
Solidarity

Enchant creature
Enchanted creature gets -1/-1.
Sacrifice an artifact: Destroy enchanted creature.

Whenever one or more creatures you control deal combat damage to a player, you may draw that many cards. If you do, discard a card.
Exile two creature cards from your graveyard: Scrapyard Mecha becomes an artifact creature until end of turn. Activate only as a sorcery.
Crew 2

Flying
Creatures you control with base power 1 or less get +1/+0.

Scuttle Tank enters with a defender counter on it.