Oath of Teferi

When Oath of Teferi enters, exile another target permanent you control. Return it to the battlefield under its owner's control at the beginning of the next end step.
You may activate the loyalty abilities of planeswalkers you control twice each turn rather than only once.

Mountain

Pledge of Loyalty

Enchant creature
Enchanted creature has protection from the colors of permanents you control. This effect doesn't remove Pledge of Loyalty.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Snow-Covered Mountain

Avacyn, Guardian Angel

Flying, vigilance
{1}{W}: Prevent all damage that would be dealt to another target creature this turn by sources of the color of your choice.
{5}{W}{W}: Prevent all damage that would be dealt to target player or planeswalker this turn by sources of the color of your choice.

Rowan, Fearless Sparkmage

+1: Up to one target creature gets +3/+0 and gains first strike until end of turn.
−2: Rowan, Fearless Sparkmage deals 1 damage to each of up to two target creatures. Those creatures can't block this turn.
−9: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Valakut Stoneforge

Valakut Stoneforge enters tapped.
{T}: Add {R}.

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Rowan's Stalwarts

When Rowan's Stalwarts enters, you may search your library and/or graveyard for a card named Rowan, Fearless Sparkmage, reveal it, and put it into your hand. If you search your library this way, shuffle.

Mountain Valley

Mountain Valley enters tapped.
{T}, Sacrifice Mountain Valley: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

The Legend of Arena

The Legend of Arena can be your commander.
I, II — Create a 2/1 red Human Wizard creature token. Spells you cast this turn cost {1} less to cast for each Wizard you control.
III — Search your library for a planeswalker card, put it onto the battlefield, then shuffle your library. It enters with an additional loyalty counter on it for each Wizard you control.

Oath of Gideon

When Oath of Gideon enters, create two 1/1 white Kor Ally creature tokens.
Each planeswalker you control enters with an additional loyalty counter on it.

The Immortal Sun

Players can't activate planeswalkers' loyalty abilities.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.
Creatures you control get +1/+1.

Fey Steed

Whenever Fey Steed attacks, another target attacking creature you control gains indestructible until end of turn.
Whenever a creature or planeswalker you control becomes the target of a spell or ability an opponent controls, you may draw a card.

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")