Can affect basic or non-basic types, but it must be for a specific type. The chosen type must be an existing land type. See the glossary of the comprehensive rulebook for more details on existing land types.

Shimmer : règles, fonctionnement et interactions (MTG)

Shimmer 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

As this enchantment enters, choose a land type. Each land of the chosen type has phasing. (It phases in or out before its controller untaps during each of their untap steps. While it's phased out, it's treated as though it doesn't exist.)

How it works : Shimmer

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2004· Wizards of the Coast
Can affect basic or non-basic types, but it must be for a specific type. The chosen type must be an existing land type. See the glossary of the comprehensive rulebook for more details on existing land types.
No other card is named in this ruling.