When Cliffwalker enters, return a permanent you control to its owner's hand.
Wander {1}{W}

Flash
When Conduit of Change enters, if you cast it, return all other nonland permanents to their owner's hands.
Spellcharge 7

Choose one —
• Target creature gets +2/+0 and gains indestructible until end of turn.
• Target player sacrifices a creature.

The next spell you cast this turn may be cast as though it had flash. When you cast that spell, copy it. You may choose new targets for the copy.
Flashback {3}{U}{U}

Destroy target artifact or land.
Flashback {4}{R}{R}

Whenever you attack, if Cursed Claymore entered this turn, attach it to target attacking creature.
Equipped creature gets +2/+1. As long as equipped creature is a Ruin, it's a creature in addition to its other types.
Equip {2}

Flash
Whenever you cast a spell during an opponent's turn, scry 1 and put a +1/+1 counter on Cutthroat Kallukah.

Flash
Daggertooth Keelah can't block unless it entered this turn.
{1}{B}, Exile a permanent card from your graveyard: Daggertooth Keelah gains indestructible until end of turn.

When Deathcap Guardian enters, exile any number of permanent cards from your graveyard. When you do, put X +1/+1 counters on Deathcap Guardian and up to one target creature gets -X/-X until end of turn, where X is the number of cards exiled this way.

Deepcavern Scyllia enters with X +1/+1 counters on it.
You may cast Deepcavern Scyllia from your graveyard by paying {3}{G} and exiling X other permanent cards from your graveyard rather than paying its mana cost.

Create a 1/1 white Human creature token, then put a +1/+1 counter on each creature you control.
Flashback {5}{W}

When Dream Catcher enters, return target exiled card with flashback you own to your hand.

As an additional cost to cast this spell, sacrifice a creature or exile two permanent cards from your graveyard.
Draw two cards.

When Elder Soulblade enters, search your library and/or graveyard for a creature card with mana value 2 or less. Put that card onto the battlefield, attach Elder Soulblade to it. If you searched you library this way, shuffle.
Equipped creature gets +3/+1 and has menace.
Equip {5}

{1}, Exile a permanent card from your graveyard: Surveil 2.
{2}, Exile two permanent cards from your graveyard: Draw a card.
{5}, Exile five permanent cards from your graveyard: Exchange your hand and graveyard.

Return up to three target creature cards from graveyards to the battlefield under your control.
Flashback—{2}{B}{B}, Sacrifice three creatures.

Target creature gets +X/+0 and gains trample until end of turn.
Draw a card.

Exile up to two target artifacts, creatures, or lands you control, then return them to the battlefield under their owner's control. If any of those permanents are Ruins, they become creatures in addition to their other types until end of turn.

Vigilance
Whenever an opponent attacks with three or more creatures, you may have Eternal Sentinel become an artifact creature until end of turn.
Spellcharge 3

When Everpresent Rot enters, create a 1/1 green Saproling creature token, surveil 1, then you gain 1 life.
When one or more permanent cards leave your graveyard, return Everpresent Rot to its owner's hand.

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Reveal the top four cards of your library. Put up to two permanent cards from among them into your hand and the rest into your graveyard. You may put land cards onto the battlefield tapped rather than your hand.
Flashback—{3}{G}, Tap an untapped Ruin you control.

Exile the top two cards of your library. You may play those cards until you next cast a spell from your hand.
Flashback {3}{R}{R}

Destroy target creature if its mana value is less than or equal to the amount of mana spent to cast this spell.
Flashback {X}{B}{B}{B}

Firebolt deals 2 damage to any target.
Flashback {4}{R}