Rakdos Guildgate

Rakdos Guildgate enters the battlefield tapped.
{T}: Add {B} or {R}.

Boros Guildgate

Boros Guildgate enters the battlefield tapped.
{T}: Add {R} or {W}.

Mr. House, President and CEO

Whenever you roll a 4 or higher, create a 3/3 colorless Robot artifact creature token. If you rolled 6 or higher, instead create that token and a Treasure token.
{4}, {T}: Roll a six-sided die plus an additional six-sided die for each mana from Treasures spent to activate this ability.

Orzhov Guildgate

Orzhov Guildgate enters the battlefield tapped.
{T}: Add {W} or {B}.