Castle Ardenvale

Castle Ardenvale enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Mask of Avacyn

Equipped creature gets +1/+2 and has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {3}

Moment of Heroism

Target creature gets +2/+2 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Patron of the Valiant

Flying
When Patron of the Valiant enters, put a +1/+1 counter on each creature you control with a +1/+1 counter on it.

Timely Ward

You may cast Timely Ward as though it had flash if it targets a commander.
Enchant creature
Enchanted creature has indestructible.

Ardenvale Fealty

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the enchantment later from exile.)

Virtue of Loyalty

At the beginning of your end step, put a +1/+1 counter on each creature you control. Untap those creatures.

Virtue of Loyalty // Ardenvale Fealty

Beloved Princess

Lifelink
Beloved Princess can't be blocked by creatures with power 3 or greater.

Animation Module

Whenever one or more +1/+1 counters are put on a permanent you control, you may pay {1}. If you do, create a 1/1 colorless Servo artifact creature token.
{3}, {T}: Choose a counter on target permanent or player. Give that permanent or player another counter of that kind.

Rustwing Falcon

Anointer of Valor

Flying
Whenever a creature attacks, you may pay {3}. When you do, put a +1/+1 counter on that creature.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Heavenly Qilin

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Heavenly Qilin attacks, another target creature you control gains flying until end of turn.

Abzan Falconer

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has flying.

Silverflame Ritual

Put a +1/+1 counter on each creature you control.
Adamant — If at least three white mana was spent to cast this spell, creatures you control gain vigilance until end of turn.

Holy Day

Prevent all combat damage that would be dealt this turn.

Ring of Thune

Equipped creature has vigilance. (Attacking doesn't cause it to tap.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's white.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Leonin Vanguard

At the beginning of combat on your turn, if you control three or more creatures, this creature gets +1/+1 until end of turn and you gain 1 life.

Elspeth, Undaunted Hero

+2: Put a +1/+1 counter on each of up to two target creatures.
−2: Search your library and/or graveyard for a card named Sunlit Hoplite and put it onto the battlefield. If you search your library this way, shuffle.
−8: Until end of turn, creatures you control gain flying and get +X/+X, where X is your devotion to white.

Prowling Felidar

Vigilance
Landfall — Whenever a land you control enters, put a +1/+1 counter on Prowling Felidar.

Plains

Fireborn Knight

Double strike
{R/W}{R/W}{R/W}{R/W}: Fireborn Knight gets +1/+1 until end of turn.

Qilin's Blessing

Target creature gets +2/+2 until end of turn.

Armory of Iroas

Whenever equipped creature attacks, put a +1/+1 counter on it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Citadel Siege

As Citadel Siege enters, choose Khans or Dragons.
• Khans — At the beginning of combat on your turn, put two +1/+1 counters on target creature you control.
• Dragons — At the beginning of combat on each opponent's turn, tap target creature that player controls.

Kinsbaile Courier

When Kinsbaile Courier enters, put a +1/+1 counter on target creature.
Encore {2}{W} ({2}{W}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)