Scion of Vitu-Ghazi

When Scion of Vitu-Ghazi enters the battlefield, if you cast it from your hand, create a 1/1 white Bird creature token with flying, then populate. (Create a token that's a copy of a creature token you control.)

Radiant, Serra Archangel

Flying
Tap another untapped creature you control with flying: Radiant, Serra Archangel gains protection from the color of your choice until end of turn.
Partner (You can have two commanders if both have partner.)

Sisay's Ring

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Serra Redeemer

Flying
Whenever another creature with power 2 or less enters the battlefield under your control, put two +1/+1 counters on that creature.

Symmetry Matrix

Whenever a creature with power equal to its toughness enters the battlefield under your control, you may pay {1}. If you do, draw a card.

Shire Shirriff

Vigilance
When Shire Shirriff enters the battlefield, you may sacrifice a token. When you do, exile target creature an opponent controls until Shire Shirriff leaves the battlefield.

Scholar of New Horizons

Scholar of New Horizons enters the battlefield with a +1/+1 counter on it.
{T}, Remove a counter from a permanent you control: Search your library for a Plains card and reveal it. If an opponent controls more lands than you, you may put that card onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand. Then shuffle.

Star Compass

Star Compass enters the battlefield tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Katerina of Myra's Marvels

As Katerina of Myra's Marvels enters the battlefield, choose a letter.
Whenever you cast a spell whose name begins with the chosen letter, create a white 2/2 Cat creature token with flying.
Partner (You can have two commanders if they both have partner.)

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Sol Talisman

Suspend 3—{1} (Rather than cast this card from your hand, pay {1} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
{T}: Add {C}{C}.

Sol Ring

Staff of the Storyteller

When Staff of the Storyteller enters the battlefield, create a 1/1 white Spirit creature token with flying.
Whenever you create one or more creature tokens, put a story counter on Staff of the Storyteller.
{W}, {T}, Remove a story counter from Staff of the Storyteller: Draw a card.

Securitron Squadron

Squad {3} (As an additional cost to cast this spell, you may pay {3} any number of times. When this creature enters the battlefield, create that many tokens that are copies of it.)
Vigilance
Whenever a creature token enters the battlefield under your control, put a +1/+1 counter on it.

Sanctifier of Souls

Whenever another creature enters the battlefield under your control, Sanctifier of Souls gets +1/+1 until end of turn.
{2}{W}, Exile a creature card from your graveyard: Create a 1/1 white Spirit creature token with flying.