Eluge, the Shoreless Sea

Eluge's power and toughness are each equal to the number of Islands you control.
Whenever Eluge enters or attacks, put a flood counter on target land. It's an Island in addition to its other types for as long as it has a flood counter on it.
The first instant or sorcery spell you cast each turn costs {U} (or {1}) less to cast for each land you control with a flood counter on it.

Gorma, the Gullet

Lifelink
Whenever another creature you control dies, put a +1/+1 counter on Gorma.
Nontoken creatures you control enter with an additional +1/+1 counter on them for each creature that died under your control this turn.

Excava, the Risen Past

Flying, haste
Whenever Excava attacks, return up to one target artifact, creature, or non-Aura enchantment card with mana value 3 or less from your graveyard to the battlefield with a finality counter on it. It's a 1/1 Spirit creature with flying in addition to its other types. (If a creature with a finality counter on it would die, exile it instead.)

Primo, the Unbounded

Trample
Primo enters with twice X +1/+1 counters on it.
Whenever one or more creatures you control with base power 0 deal combat damage to a player, create a 0/0 green and blue Fractal creature token. Put a number of +1/+1 counters on it equal to the damage dealt.

Blech, Loafing Pest

Whenever you gain life, put a +1/+1 counter on each Pest, Bat, Insect, Snake, and Spider you control.

Scriv, the Obligator

Flying, deathtouch
Whenever Scriv enters or attacks, create a white Aura enchantment token named Contract attached to target creature an opponent controls. The token has enchant creature and "Whenever enchanted creature attacks, it gets +2/+0 until end of turn if it's attacking one of your opponents. Otherwise, its controller loses 2 life."

Taigam, Sidisi's Hand

Skip your draw step.
At the beginning of your upkeep, look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
{B}, {T}, Exile X cards from your graveyard: Target creature gets -X/-X until end of turn.

Witherbloom, the Balancer

Affinity for creatures (This spell costs {1} less to cast for each creature you control.)
Flying, deathtouch
Instant and sorcery spells you cast have affinity for creatures.