Grim Affliction

Put a -1/-1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Snake Umbra

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

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.

Swamp

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.

Untamed Might

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

Island

Crystal Grotto

When Crystal Grotto enters the battlefield, scry 1.
{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Not Dead After All

Until end of turn, target creature you control gains "When this creature dies, return it to the battlefield tapped under its owner's control, then create a Wicked Role token attached to it." (Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Plague Stinger

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

Giant Growth

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

Sugar Rush

Target creature gets +3/+0 until end of turn.
Draw a card.

Terramorphic Expanse

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

Apostle's Blessing

({W/P} can be paid with either {W} or 2 life.)
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn.

Candy Trail

When Candy Trail enters the battlefield, scry 2.
{2}, {T}, Sacrifice Candy Trail: You gain 3 life and draw a card.

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.)

Shimmering Grotto

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Mutagenic Growth

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

Doom Blade

Forest

Abundant Growth

Enchant land
When Abundant Growth enters the battlefield, draw a card.
Enchanted land has "{T}: Add one mana of any color."