Witherscale Wurm

Whenever Witherscale Wurm blocks or becomes blocked by a creature, that creature gains wither until end of turn. (It deals damage to creatures in the form of -1/-1 counters.)
Whenever Witherscale Wurm deals damage to an opponent, remove all -1/-1 counters from it.

Duskdale Wurm

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Bookwurm

Trample
When Bookwurm enters the battlefield, you gain 3 life and draw a card.
{2}{G}: Put Bookwurm from your graveyard into your library third from the top.

Elderscale Wurm

Trample
When Elderscale Wurm enters the battlefield, if your life total is less than 7, your life total becomes 7.
As long as you have 7 or more life, damage that would reduce your life total to less than 7 reduces it to 7 instead.

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.

Worldspine Wurm

Trample
When Worldspine Wurm dies, create three 5/5 green Wurm creature tokens with trample.
When Worldspine Wurm is put into a graveyard from anywhere, shuffle it into its owner's library.

Grothama, All-Devouring

Other creatures have "Whenever this creature attacks, you may have it fight Grothama, All-Devouring."
When Grothama leaves the battlefield, each player draws cards equal to the amount of damage dealt to Grothama this turn by sources they controlled.

Engulfing Slagwurm

Whenever Engulfing Slagwurm blocks or becomes blocked by a creature, destroy that creature. You gain life equal to that creature's toughness.

Bramble Wurm

Reach, trample
When Bramble Wurm enters the battlefield, you gain 5 life.
{2}{G}, Exile Bramble Wurm from your graveyard: You gain 5 life.

Roaring Slagwurm

Whenever Roaring Slagwurm attacks, tap all artifacts.

Plated Slagwurm

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

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.

Sifter Wurm

Trample
When Sifter Wurm enters the battlefield, scry 3, then reveal the top card of your library. You gain life equal to that card's mana value.

Battering Wurm

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters the battlefield with a +1/+1 counter on it.)
Creatures with power less than Battering Wurm's power can't block it.

Yavimaya Wurm

Wurmcoil Engine

Deathtouch, lifelink
When Wurmcoil Engine dies, create a 3/3 colorless Phyrexian Wurm artifact creature token with deathtouch and a 3/3 colorless Phyrexian Wurm artifact creature token with lifelink.

Conifer Wurm

Trample
{3}{G}: Conifer Wurm gets +X/+X until end of turn, where X is the number of snow permanents you control.

Garruk, Primal Hunter

+1: Create a 3/3 green Beast creature token.
−3: Draw cards equal to the greatest power among creatures you control.
−6: Create a 6/6 green Wurm creature token for each land you control.

Deathcoil Wurm

You may have Deathcoil Wurm assign its combat damage as though it weren't blocked.

Dirtcowl Wurm

Whenever an opponent plays a land, put a +1/+1 counter on Dirtcowl Wurm.

Panglacial Wurm

Trample
While you're searching your library, you may cast Panglacial Wurm from your library.

Ravenous Lindwurm

When Ravenous Lindwurm enters the battlefield, you gain 4 life.

Penumbra Wurm

Trample
When Penumbra Wurm dies, create a 6/6 black Wurm creature token with trample.

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