Plaza of Harmony — ruling 1

The types of mana are white, blue, black, red, green, and colorless.

Plaza of Harmony — ruling 2

Any additions to a Gate’s land types or abilities gained by a Gate can affect the types of mana a Gate can produce.

Plaza of Harmony — ruling 3

Plaza of Harmony checks the effects of all mana-producing abilities of Gates you control, but it doesn’t check their costs or legality. For example, it doesn’t check whether a Gate is untapped.

Plaza of Harmony : règles, fonctionnement et interactions (MTG)

Plaza of Harmony is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

When this land enters, if you control two or more Gates, you gain 3 life. : Add . : Add one mana of any type that a Gate you control could produce.

How it works : Plaza of Harmony

Original English text — Wizards of the Coast / Scryfall

#1January 25, 2019· Wizards of the Coast
The types of mana are white, blue, black, red, green, and colorless.
No other card is named in this ruling.
#2January 25, 2019· Wizards of the Coast
Any additions to a Gate’s land types or abilities gained by a Gate can affect the types of mana a Gate can produce.
No other card is named in this ruling.
#3January 25, 2019· Wizards of the Coast
Plaza of Harmony checks the effects of all mana-producing abilities of Gates you control, but it doesn’t check their costs or legality. For example, it doesn’t check whether a Gate is untapped.
No other card is named in this ruling.