Next week I'm going to go shopping for some sax music now I can get all notes out nicely (including all the bottom notes) and can play scales & arpeggios in all keys at a good pace. I can easily sight read grade 5-6ish clarinet stuff (albeit in the wrong key as I'm not amazing at sight transposition) on my sax and would like to get some music in a jazz / blues style for my sax.

Would like some to be not too much of a challenge and some to be long term projects.

I like the Bob Mintzer books - there are 3 of them. The "Easy" book is probably about grade 5ish. The other two "Blues & Funk Etudes" and "Jazz & Funk Etudes" are quite a lot harder, with the Blues & Funk being slightly easier. Lennie Niehaus jazz etudes books are good, so is Jim Snidero "Intermediate Jazz Conception"

If you are going to buy the Mintzer books, and I agree they are good, make sure you get the one with the cd fastened to the back in a plastic wallet. We had loads of problems with the ones in card as the glue has leaked through on to the cds. They won't play on all devices and they are particularly quiet.