At the Fluent level, more variety of genres and language structures are introduced including Play, Procedural, Narrative, Recount, Science Fiction, Humour etc. Children will be exposed a variety of language structures and at the same time expanding his/her vocabulary.
See some samples:
Factual (Unusual trees)

Excerpt: Terrific Trees (Fluent 1, Non-Fiction)
A Play (Featuring script with Scenes)
Excerpt: The Giant Jumperee (Fluent 1, Fiction)
Factual (Featuring Pie Chart)

Excerpt: Paper Crunch (Fluent 1, Non-Fiction)
Narrative (Fantasy Adventure)

Excerpt: Fizzkid the Inventor (Fluent 1, Fiction)
Narrative (Making Assumptions about People)

Excerpt: The Mystery Man (Fluent 2, Fiction)
Factual/Historical (Footwear through different times/culture)
Excerpt: Stepping Through Time (Fluent 3, Non-fiction)
Expository (Diary Writing with Flowchart)
Excerpt: The Ice-cream Factory (Fluent 3, Non-fiction)
Narrative (Doing what you are best at)

Excerpt: The Piano Recital (Fluent 3, Fiction)
Traditional Tale

Excerpt: Head First into the Porridge (Fluent 3, Fiction)
Science Fiction
Excerpt: Space Station Orion (Fluent 4, Fiction)
Traditional Tale

Excerpt: Always Elephant (Fluent 4, Fiction)
Factual

Excerpt: Teeth, Fluent 4, Non-fiction