Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Undercity Sewers

({T}: Add {U} or {B}.)
Undercity Sewers enters tapped.
When Undercity Sewers enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Sol Ring

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Island

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Wrexial, the Risen Deep

Islandwalk, swampwalk (This creature can't be blocked as long as defending player controls an Island or a Swamp.)
Whenever Wrexial, the Risen Deep deals combat damage to a player, you may cast target instant or sorcery card from that player's graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Sky Diamond

Urborg, Tomb of Yawgmoth

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

Dimir Signet

Arcane Signet

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

Swamp

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.