Whisper Agent

Flash
When Whisper Agent enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Rhizome Lurcher

Undergrowth — Rhizome Lurcher enters with a number of +1/+1 counters on it equal to the number of creature cards in your graveyard.

Hired Poisoner

Barrier of Bones

Defender
When Barrier of Bones enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Glowspore Shaman

When Glowspore Shaman enters, mill three cards. You may put a land card from your graveyard on top of your library. (To mill a card, put the top card of your library into your graveyard.)

Molderhulk

Undergrowth — This spell costs {1} less to cast for each creature card in your graveyard.
When Molderhulk enters, return target land card from your graveyard to the battlefield.

Torgaar, Famine Incarnate

As an additional cost to cast this spell, you may sacrifice any number of creatures. This spell costs {2} less to cast for each creature sacrificed this way.
When Torgaar, Famine Incarnate enters, up to one target player's life total becomes half their starting life total, rounded down.