Focusing on the collection aspect:
* Single work: This emphasizes that it's not a collection, but a single piece.
* Individual piece: Similar to "single work," highlighting the lack of a collection.
* Original work: This emphasizes that the work is not compiled from others.
Focusing on the variety of content:
* Monograph: This focuses on a single topic, unlike an anthology's variety.
* Specialized work: Similar to "monograph," emphasizing a focused topic instead of a variety of content.
Focusing on the authors:
* Solo work: This emphasizes a single author, unlike the multiple authors in an anthology.
* Individual author's work: Similar to "solo work," highlighting the single author.
Ultimately, the best antonym depends on the specific context of your usage.