Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Troll of Khazad-dûm

Troll of Khazad-dûm can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Snow-Covered Island

Volatile Fjord

({T}: Add {U} or {R}.)
Volatile Fjord enters tapped.

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters tapped.

Have

Generous Ent

Reach
When Generous Ent enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Forestcycling {1} ({1}, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)

Woodland Chasm

({T}: Add {B} or {G}.)
Woodland Chasm enters tapped.

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Cast Down

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Oliphaunt

Trample
Whenever Oliphaunt attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Sulfurous Mire

({T}: Add {B} or {R}.)
Sulfurous Mire enters tapped.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)