However, you could use these options:
* Set of encyclopedias
* Collection of encyclopedias
* Series of encyclopedias
* Library of encyclopedias (if referring to a large collection)
You could also use a more descriptive phrase, depending on the context:
* A comprehensive resource of knowledge
* A collection of authoritative texts
* A treasure trove of information
Ultimately, the best choice depends on the specific situation and the intended meaning.