Vigilance, reach
When Thundering Serpent enters, you gain 6 life.

When Towering Sentinel enters, for each kind of counter among permanents you control, put a counter of that kind on Towering Sentinel, then add {G} or {U}.

Approval — When Triumphant Herd enters, you gain X life, where X is the number of colors among permanents you control.

When Vishanki Ambassador enters, each opponent loses 3 life and you gain 3 life.
Basic landcycling {1}{R}

The first spell you cast during each of your turns costs {R}{G} less to cast.
You may play two additional lands on each of your turns.
Landfall — Whenever a land you control enters, you may exile the top three cards of your library. You may play those cards from exile as long as you control Warden of Tremors.

As long as you control four or more lands with different names, Worldtreader Beast can't be blocked by creatures with power 2 or less.

Flash
{2}{B}, Discard Zyxthax Apex: Each opponent loses 3 life and you gain 3 life.
{6}{B}{B}: Return Zyxthax Apex from your graveyard to the battlefield tapped with a finality counter on it.

Menace
Drop — Whenever Avatar of the Decks or another creature you control enters, if the entering creature was cast, sacrifice a permanent unless you didn't cast any creature spells during your last turn.

Haste
Drop — Whenever Avatar of the Moshpit or another creature you control enters, if the entering creature was cast and you didn't cast any creature spells during your last turn, discard your hand, then draw three cards.

Reach
Drop — Whenever Avatar of the Rave or another creature you control enters, if the entering creature was cast and you didn't cast any creature spells during your last turn, return up to two target cards from your graveyard to your hand.

Flash
Ward {3}
You may reveal the second card you draw each turn as you draw it. When you do, you may cast it without paying its mana cost. If you didn't cast a spell this way, create two Treasure tokens.

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

All spells cost {1} more to cast.
Spellcharge 6

Flash
Approval — When Congressional Kraken enters, return each nonland permanent with mana value less than or equal to the number of colors among permanents you control to their owners' hands.

Flash
When Corrosive Spitter enters, destroy all creatures that were dealt damage this turn.

Hexproof
When Dakran Shipcrusher enters, you may bless target creature.

Ward {3}
Daunting Snapper can't be blocked by creatures with power 2 or less.

Whenever Devourer of Fortunes enters or attacks, return up to one target instant or sorcery card in a graveyard or creature on the battlefield to its owner's hand. You may cast a copy of it, and may spend mana of any type to cast it.

If you have more life than your starting life total, this spell costs {X} less to cast, where X is equal to the difference.
Trample
When Glacier Guardian enters, you may have it fight target creature you don't control.

At the beginning of your end step, if you cast no spells this turn, surveil 1.
Spellcharge 6

Trample
When Hunger's Door enters, you may return target Aura card from your graveyard to the battlefield attached to Hunger's Door.

King of Currents can't attack unless there are six or more cards in your graveyard.
Surface {4}{U}{U}

Reach
Surface {4}{G}{G}

Flying
Whenever Molten Slagmaw enters or attacks, each opponent sacrifices an artifact or nonbasic land.

Trample
Amity — Whenever Old-Growth Gecko attacks, put a +1/+1 counter on another creature you control. If exactly one other creature attacked with it, this ability triggers three times instead.