Thought-Stalker Warlock

Menace (This creature can't be blocked except by two or more creatures.)
When Thought-Stalker Warlock enters, choose target opponent. If they lost life this turn, they reveal their hand, you choose a nonland card from it, and they discard that card. Otherwise, they discard a card.

Valley Rotcaller

Menace
Whenever Valley Rotcaller attacks, each opponent loses X life and you gain X life, where X is the number of other Squirrels, Bats, Lizards, and Rats you control.

Gev, Scaled Scorch

Ward—Pay 2 life.
Other creatures you control enter with an additional +1/+1 counter on them for each opponent who lost life this turn.
Whenever you cast a Lizard spell, Gev, Scaled Scorch deals 1 damage to target opponent.

Swamp

Scales of Shale

This spell costs {1} less to cast for each Lizard you control.
Target creature gets +2/+0 and gains lifelink and indestructible until end of turn.

Valley Flamecaller

If a Lizard, Mouse, Otter, or Raccoon you control would deal damage to a permanent or player, it deals that much damage plus 1 instead.

Steampath Charger

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature dies, it deals 1 damage to target player.

Mountain

Savor

Target creature gets -2/-2 until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Iridescent Vinelasher

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.

Flamecache Gecko

When Flamecache Gecko enters, if an opponent lost life this turn, add {B}{R}.
{1}{R}, Discard a card: Draw a card.

Hired Claw

Whenever you attack with one or more Lizards, Hired Claw deals 1 damage to target opponent.
{1}{R}: Put a +1/+1 counter on Hired Claw. Activate only if an opponent lost life this turn and only once each turn.