Have

Llanowar Elves

Infectious Bite

Target creature you control deals damage equal to its power to target creature you don't control. Each opponent gets a poison counter.

Bloated Contaminator

Trample
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever this creature deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Scavenging Ooze

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on this creature and you gain 1 life.

Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Elvish Mystic

Venomous Brutalizer

Toxic 3 (Players dealt combat damage by this creature also get three poison counters.)
When this creature enters, you may pay {1}{G}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Planewide Celebration

Choose four. You may choose the same mode more than once.
• Create a 2/2 Citizen creature token that's all colors.
• Return target permanent card from your graveyard to your hand.
• Proliferate.
• You gain 4 life.

Prosthetic Injector

Equipped creature gets +0/+2 and has toxic 1. (Players dealt combat damage by equipped creature also get a poison counter.)
Equip {1}

Forest

Old-Growth Troll

Trample
When Old-Growth Troll dies, if it was a creature, return it to the battlefield. It's an Aura enchantment with enchant Forest you control and "Enchanted Forest has '{T}: Add {G}{G}' and '{1}, {T}, Sacrifice this land: Create a tapped 4/4 green Troll Warrior creature token with trample.'"

Getting

Steel Leaf Champion

This creature can't be blocked by creatures with power 2 or less.

Lair of the Hydra

If you control two or more other lands, this land enters tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, this land becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (A creature with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Questing Beast

Vigilance, deathtouch, haste
Questing Beast can't be blocked by creatures with power 2 or less.
Combat damage that would be dealt by creatures you control can't be prevented.
Whenever Questing Beast deals combat damage to an opponent, it deals that much damage to target planeswalker that player controls.

Tyrranax Rex

This spell can't be countered.
Trample, ward {4}, haste
Toxic 4 (Players dealt combat damage by this creature also get four poison counters.)

Viral Spawning

Create a 3/3 green Phyrexian Beast creature token with toxic 1. (Players dealt combat damage by it also get a poison counter.)
Corrupted — As long as an opponent has three or more poison counters and this card is in your graveyard, it has flashback {2}{G}. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Audacity

Enchant creature
Enchanted creature gets +2/+0 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
When this Aura is put into a graveyard from the battlefield, draw a card.

Mirrex

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if this land entered this turn.
{3}, {T}: Create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block." (Players dealt combat damage by it also get a poison counter.)

Ghalta, Primal Hunger

This spell costs {X} less to cast, where X is the total power of creatures you control.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Werewolf Pack Leader

Pack tactics — Whenever this creature attacks, if you attacked with creatures with total power 6 or greater this combat, draw a card.
{3}{G}: Until end of turn, this creature has base power and toughness 5/3, gains trample, and isn't a Human.

Aspect of Hydra

Target creature gets +X/+X until end of turn, where X is your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)