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.

Scry 3, then draw three cards.
If this spell's flashback cost was paid, take an extra turn after this one.
Flashback {7}{U}{U}

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}

When Elderflame Pilgrims enters, it deals 2 damage to target player or planeswalker.
Wander {5}{R}

Exile target creature you control, then return that card to the battlefield under your control with an additional +1/+1 counter on it.

{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.

Vigilance
At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, put a +1/+1 counter on Encampment Sentinel.

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.

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}

Flying
{T}: Add {C}.
Spellcharge 4

Equipped creature gets +2/+2 and can't be blocked by more than one creature.
Equip {4}

Enchant permanent
Enchanted permanent can't attack, block, or wander.

When Forgemaster Dreadnought enters, create three Treasure tokens.
Spellcharge 9

Choose target card in a graveyard other than a basic land. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. You gain 1 life for each card exiled this way. That player draws a card for each card exiled from their hand this way.
Flashback {3}{B}

{1}{B}, Exile two permanent cards from your graveyard: Choose one —
• Create two 1/1 green Saproling creature tokens.
• Exile the top card of target opponent's library. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast it.

Target creature you control gains double strike until end of turn. It deals damage equal to its power to each of up to two other targets.