maybe

Atomize

Destroy target nonland permanent. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Have Slot

Vector Asp

{B}: Vector Asp gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Invigorate

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life.
Target creature gets +4/+4 until end of turn.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap Staff of Compleation.

Embiggen

Until end of turn, target non-Brushwagg creature gets +1/+1 for each supertype, card type, and subtype it has.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Old-Growth Grove

Old-Growth Grove enters tapped.
{T}: Add {B} or {G}.

Revitalizing Repast

Put a +1/+1 counter on target creature. It gains indestructible until end of turn.

Revitalizing Repast // Old-Growth Grove

Inkmoth Nexus

{T}: Add {C}.
{1}: Inkmoth Nexus becomes a 1/1 Phyrexian Blinkmoth artifact creature with flying and infect until end of turn. It's still a land. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Otrimi, the Ever-Playful

Mutate {1}{B}{G}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Trample
Whenever this creature deals combat damage to a player, return target creature card with mutate from your graveyard to your hand.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Getting

Pick Your Poison

Choose one —
• Each opponent sacrifices an artifact.
• Each opponent sacrifices an enchantment.
• Each opponent sacrifices a creature with flying.

Snakeskin Veil

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)