Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Sandsteppe Citadel

Sandsteppe Citadel enters tapped.
{T}: Add {W}, {B}, or {G}.

Child of Alara

Trample
When Child of Alara dies, destroy all nonland permanents. They can't be regenerated.

Indestructible Aura

Prevent all damage that would be dealt to target creature this turn.

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Desynchronization

Return each nonland permanent that's not historic to its owner's hand. (Artifacts, legendaries, and Sagas are historic.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Havi, the All-Father

Havi, the All-Father has indestructible as long as there are four or more historic cards in your graveyard. (Artifacts, legendaries, and Sagas are historic.)
Sage Project — Whenever Havi or another legendary creature you control dies, return target legendary creature card with lesser mana value from your graveyard to the battlefield tapped.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

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.)

Exotic Orchard

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Twisted Landscape

{T}: Add {C}.
{T}, Sacrifice Twisted Landscape: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{R}{G} ({B}{R}{G}, Discard this card: Draw a card.)

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Aegis Angel

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Aegis Angel enters, another target permanent gains indestructible for as long as you control Aegis Angel. (Effects that say "destroy" don't destroy it. A creature with indestructible can't be destroyed by damage.)

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Arcane Signet

Tranquil Landscape

{T}: Add {C}.
{T}, Sacrifice Tranquil Landscape: Search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle.
Cycling {G}{W}{U} ({G}{W}{U}, Discard this card: Draw a card.)

Assassin Initiate

{1}: Assassin Initiate gains your choice of flying, deathtouch, or lifelink until end of turn.