Cephalid Sage

Threshold — As long as seven or more cards are in your graveyard, Cephalid Sage has "When Cephalid Sage enters, draw three cards, then discard two cards."

Island

Forest

Far Wanderings

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
Threshold — If seven or more cards are in your graveyard, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Reality Acid

Enchant permanent
Vanishing 3 (This Aura enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Reality Acid leaves the battlefield, enchanted permanent's controller sacrifices it.

Vigorspore Wurm

Undergrowth — When Vigorspore Wurm enters, target creature gains vigilance and gets +X/+X until end of turn, where X is the number of creature cards in your graveyard.
Vigorspore Wurm can't be blocked by more than one creature.

Satyr Wayfinder

When Satyr Wayfinder enters, reveal the top four cards of your library. You may put a land card from among them into your hand. Put the rest into your graveyard.

Pieces of the Puzzle

Reveal the top five cards of your library. Put up to two instant and/or sorcery cards from among them into your hand and the rest into your graveyard.

Undergrowth Scavenger

Undergrowth Scavenger enters with a number of +1/+1 counters on it equal to the number of creature cards in all graveyards.

Krosan Restorer

{T}: Untap target land.
Threshold — {T}: Untap up to three target lands. Activate only if seven or more cards are in your graveyard.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Taigam's Scheming

Surveil 5. (Look at the top five cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Grapple with the Past

Mill three cards, then you may return a creature or land card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Walker of the Grove

When Walker of the Grove leaves the battlefield, create a 4/4 green Elemental creature token.
Evoke {4}{G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Contingency Plan

Displace

Exile up to two target creatures you control, then return those cards to the battlefield under their owner's control.

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.