Boneyard Wurm

Boneyard Wurm's power and toughness are each equal to the number of creature cards in your graveyard.

Baru, Wurmspeaker

Wurms you control get +2/+2 and have trample.
{7}{G}, {T}: Create a 4/4 green Wurm creature token. This ability costs {X} less to activate, where X is the greatest power among Wurms you control.

Sol Ring

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Bellowing Tanglewurm

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Other green creatures you control have intimidate.

Impervious Greatwurm

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Indestructible

Sandwurm Convergence

Creatures with flying can't attack you or planeswalkers you control.
At the beginning of your end step, create a 5/5 green Wurm creature token.