While we have "a flock of birds," "a herd of elephants," and "a pack of wolves," there's no established term for a collection of prose.
However, you could use some creative options depending on the context:
* A body of prose - emphasizes the large amount of written work
* A tapestry of prose - suggests diverse and interwoven styles
* A collection of prose - a simple and straightforward option
* A compendium of prose - implies a comprehensive or authoritative collection
* A suite of prose - suggests a connected group of works with a shared theme or style
Ultimately, the best choice depends on the specific context and the desired effect.