Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Island

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

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

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

({T}: Add {U}, {B}, or {R}.)
Xander's Lounge enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Menace
Whenever Obeka, Splitter of Seconds deals combat damage to a player, you get that many additional upkeep steps after this phase.