Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Skitter of Lizards

Multikicker {1}{R} (You may pay an additional {1}{R} any number of times as you cast this spell.)
Haste
Skitter of Lizards enters with a +1/+1 counter on it for each time it was kicked.

Flameblade Adept

Menace
Whenever you cycle or discard a card, Flameblade Adept gets +1/+0 until end of turn.

Amber Gristle O'Maul

Haste
Whenever Amber Gristle O'Maul attacks, you may discard your hand. If you do, draw a card for each player being attacked.
Choose a Background (You can have a Background as a second commander.)

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Rosnakht, Heir of Rohgahh

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Heroic — Whenever you cast a spell that targets Rosnakht, Heir of Rohgahh, create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Insolent Neonate

Menace (This creature can't be blocked except by two or more creatures.)
Discard a card, Sacrifice Insolent Neonate: Draw a card.

Mist-Cloaked Herald

Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Gudul Lurker

Gudul Lurker can't be blocked.
Megamorph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Dragonmaster Outcast

At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying.

Foundry Street Denizen

Whenever another red creature you control enters, Foundry Street Denizen gets +1/+0 until end of turn.

Mausoleum Wanderer

Flying
Whenever another Spirit you control enters, Mausoleum Wanderer gets +1/+1 until end of turn.
Sacrifice Mausoleum Wanderer: Counter target instant or sorcery spell unless its controller pays {X}, where X is Mausoleum Wanderer's power.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Goblin Glory Chaser

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
As long as Goblin Glory Chaser is renowned, it has menace. (It can't be blocked except by two or more creatures.)

Falkenrath Pit Fighter

{1}{R}, Discard a card, Sacrifice a Vampire: Draw two cards. Activate only if an opponent lost life this turn.

Slither Blade

Cobbled Lancer

As an additional cost to cast this spell, exile a creature card from your graveyard.
{3}{U}, Exile Cobbled Lancer from your graveyard: Draw a card.

Artificer's Assistant

Flying
Whenever you cast a historic spell, scry 1. (Artifacts, legendaries, and Sagas are historic. To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Faerie Seer

Flying
When Faerie Seer enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Cloudfin Raptor

Flying
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Ascendant Spirit

{S}{S}: Ascendant Spirit becomes a Spirit Warrior with base power and toughness 2/3.
{S}{S}{S}: If Ascendant Spirit is a Warrior, put a flying counter on it and it becomes a Spirit Warrior Angel with base power and toughness 4/4.
{S}{S}{S}{S}: If Ascendant Spirit is an Angel, put two +1/+1 counters on it and it gains "Whenever this creature deals combat damage to a player, draw a card."

Lanterns' Lift

Enchant creature
Enchanted creature gets +1/+1 and has flying.
If Lanterns' Lift would be put into a graveyard from anywhere, exile it instead.

Lantern Bearer

Flying
Disturb {2}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Lantern Bearer // Lanterns' Lift

Hypnotic Siren

Bestow {5}{U}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
You control enchanted creature.
Enchanted creature gets +1/+1 and has flying.

Moonrise Intruder

Menace (This creature can't be blocked except by two or more creatures.)
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Moonrise Intruder.

Village Messenger

Haste
At the beginning of each upkeep, if no spells were cast last turn, transform Village Messenger.

Village Messenger // Moonrise Intruder

Phantasmal Bear

When Phantasmal Bear becomes the target of a spell or ability, sacrifice it.

Expendable Lackey

{1}{U}, Exile Expendable Lackey from your graveyard: Create a 1/1 blue Fish creature token with "This creature can't be blocked." Activate only as a sorcery.

Triton Shorestalker

Network Disruptor

Flying
When Network Disruptor enters, tap target permanent.

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Ghitu Lavarunner

As long as there are two or more instant and/or sorcery cards in your graveyard, this creature gets +1/+0 and has haste. (It can attack and {T} as soon as it comes under your control.)

Wingcrafter

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Wingcrafter is paired with another creature, both creatures have flying.

Kessig Wolfrider

Menace
{2}{R}, {T}, Exile three cards from your graveyard: Create a 3/2 red Wolf creature token.

Feywild Visitor

Commander creatures you own have "Whenever one or more nontoken creatures you control deal combat damage to a player, you create a 1/1 blue Faerie Dragon creature token with flying."

Stromkirk Noble

This creature can't be blocked by Humans.
Whenever this creature deals combat damage to a player, put a +1/+1 counter on it.