Mulch

Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Savannah

Nimble Mongoose

Shroud (This creature can't be the target of spells or abilities.)
Threshold — Nimble Mongoose gets +2/+2 as long as seven or more cards are in your graveyard.

Mystic Visionary

Threshold — Mystic Visionary has flying as long as seven or more cards are in your graveyard.

Coastal Tower

Coastal Tower enters tapped.
{T}: Add {W} or {U}.

Island

Elfhame Palace

Elfhame Palace enters tapped.
{T}: Add {G} or {W}.

Anurid Barkripper

Threshold — Anurid Barkripper gets +2/+2 as long as seven or more cards are in your graveyard.

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Seton's Scout

Reach (This creature can block creatures with flying.)
Threshold — Seton's Scout gets +2/+2 as long as seven or more cards are in your graveyard.

Mystic Familiar

Flying
Threshold — As long as seven or more cards are in your graveyard, Mystic Familiar gets +1/+1 and has protection from black.

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Accumulated Knowledge

Draw a card, then draw cards equal to the number of cards named Accumulated Knowledge in all graveyards.

Armageddon

Werebear

{T}: Add {G}.
Threshold — Werebear gets +3/+3 as long as seven or more cards are in your graveyard.