Wall of Forgotten Pharaohs — ruling 1

If an ability checks whether you control a Desert or there is a Desert card in your graveyard, having more than one doesn't matter. Controlling one is the same as controlling five. There is also no extra bonus for both controlling one and having one in your graveyard.

Wall of Forgotten Pharaohs : règles, fonctionnement et interactions (MTG)

Wall of Forgotten Pharaohs 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

Defender : This creature deals 1 damage to target player or planeswalker. Activate only if you control a Desert or there is a Desert card in your graveyard.

How it works : Wall of Forgotten Pharaohs

Original English text — Wizards of the Coast / Scryfall

#1July 14, 2017· Wizards of the Coast
If an ability checks whether you control a Desert or there is a Desert card in your graveyard, having more than one doesn't matter. Controlling one is the same as controlling five. There is also no extra bonus for both controlling one and having one in your graveyard.
No other card is named in this ruling.