Unholy Citadel

Black legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Pendelhaven

{T}: Add {G}.
{T}: Target 1/1 creature gets +1/+2 until end of turn.

Mountain Stronghold

Red legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Time of Need

Search your library for a legendary creature card, reveal it, put it into your hand, then shuffle.

Seafarer's Quay

Blue legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Untaidake, the Cloud Keeper

Untaidake enters tapped.
{T}, Pay 2 life: Add {C}{C}. Spend this mana only to cast legendary spells.

Tolaria

{T}: Add {U}.
{T}: Target creature loses banding and all "bands with other" abilities until end of turn. Activate only during any upkeep step.

Honor-Worn Shaku

{T}: Add {C}.
Tap an untapped legendary permanent you control: Untap this artifact.

Primevals' Glorious Rebirth

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Return all legendary permanent cards from your graveyard to the battlefield.

Heroes' Podium

Each legendary creature you control gets +1/+1 for each other legendary creature you control.
{X}, {T}: Look at the top X cards of your library. You may reveal a legendary creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Jodah, Archmage Eternal

Flying
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Cathedral of Serra

White legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Urza's Ruinous Blast

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Exile all nonland permanents that aren't legendary.

Leyline of Singularity

If this card is in your opening hand, you may begin the game with it on the battlefield.
All nonland permanents are legendary.

Day of Destiny

Legendary creatures you control get +2/+2.

Adventurers' Guildhouse

Green legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Urborg

{T}: Add {B}.
{T}: Target creature loses first strike or swampwalk until end of turn.