Boreas Charger — ruling 1

You can find fewer Plains cards than the difference, perhaps because you don't have that many Plains cards left in your library.

Boreas Charger — ruling 2

If no opponent controls more lands than you, you'll search your library and shuffle it, but you won't be able to find any Plains cards.

Boreas Charger : règles, fonctionnement et interactions (MTG)

Boreas Charger 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

Flying When this creature leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle.

How it works : Boreas Charger

Original English text — Wizards of the Coast / Scryfall

#1July 13, 2018· Wizards of the Coast
You can find fewer Plains cards than the difference, perhaps because you don't have that many Plains cards left in your library.
No other card is named in this ruling.
#2July 13, 2018· Wizards of the Coast
If no opponent controls more lands than you, you'll search your library and shuffle it, but you won't be able to find any Plains cards.
No other card is named in this ruling.