Flashback

Target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Garrison Excavator

Menace (This creature can't be blocked except by two or more creatures.)
Whenever one or more cards leave your graveyard, create a 2/2 red and white Spirit creature token.

Rubble Rouser

When this creature enters, you may discard a card. If you do, draw a card.
{T}, Exile a card from your graveyard: Add {R}. When you do, this creature deals 1 damage to each opponent.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Conspiracy Theorist

Whenever this creature attacks, you may pay {1} and discard a card. If you do, draw a card.
Whenever you discard one or more nonland cards, you may exile one of them from your graveyard. If you do, you may cast it this turn.

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Advanced Reconstruction

(Gain the next level as a sorcery to add its ability.)
At the beginning of your first main phase, mill a card, then exile a card from your graveyard at random. You may play the exiled card this turn.
{1}{R}: Level 2
Whenever one or more cards leave your graveyard, this Class deals 2 damage to each opponent.
{1}{R}: Level 3
Spells you cast from anywhere other than your hand cost {2} less to cast.

Recoup

Target sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (Mana cost includes color.)
Flashback {3}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Relic Retriever

First strike
At the beginning of each end step, if a card left your graveyard this turn, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Gau, Feral Youth

Rage — Whenever Gau attacks, put a +1/+1 counter on it.
At the beginning of each end step, if a card left your graveyard this turn, Gau deals damage equal to its power to each opponent.

Spirit of Resilience

Whenever one or more cards leave your graveyard, put a +1/+1 counter on this creature, then you may have this creature become a copy of an artifact or creature card from among those cards until end of turn.