Glistener Elf

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Llanowar Augur

Sacrifice Llanowar Augur: Target creature gets +3/+3 and gains trample until end of turn. Activate only during your upkeep.

Swamp

Might of Old Krosa

Target creature gets +2/+2 until end of turn. If you cast this spell during your main phase, that creature gets +4/+4 until end of turn instead.

Forest

Giant Growth

Target creature gets +3/+3 until end of turn.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Island

Groundswell

Target creature gets +2/+2 until end of turn.
Landfall — If you had a land enter the battlefield under your control this turn, that creature gets +4/+4 until end of turn instead.

Vines of Vastwood

Kicker {G} (You may pay an additional {G} as you cast this spell.)
Target creature can't be the target of spells or abilities your opponents control this turn. If this spell was kicked, that creature gets +4/+4 until end of turn.

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.