Can anyone recommend a series of books for ds to read at home to support his school reading?

[Carrotsandcelery]

Ds is currently reading stage 5 of Oxford Reading Tree at school but can easily read stage 8 at home.
I bought a few ORT for at home but I don't want to buy more as it is boring enough for him having to trudge through every single book available in each stage, without having to do those ones at home too (and I can no longer get ORT Read At Home books at these levels.)
I have hunted around the bookshops and library for a series that he could read at home without reading ORT but which follows a similar progression.
I am overwhelmed by the choice out there and wondered if anyone could recommend a series to keep him interested?

Flat Stanley series Jeff Brown
Fantastic Mr. Fox and others by Roald Dahl
George Speaks and other titles by Dick King Smith

These are all books that work well with emergent readers, I agree.
And do have a look at the wonderful Lobel books - there are Mouse Tales and Owl at Home - which are delicious - as well as the Frog and Toad books that school libraries usually have.

I'd try to wean him off phonic series at this stage, if you can, or at least stick to those that are written by childrens' authors, such as Julia Donaldson's Songbirds (these are v. expensive, so it's worth seeing if your library has them).

Sarah the Corgi Pups arrived today and have gone down brilliantly with ds. Dd also made off with them and was reading them to him. Thank you for a great suggestion. Happy little 6 year old.

Second Flat Stanley - we love him
Oliver Moon is good too
Usborne Puzzle Adventures - story plus a code to crack and clues etc