I am enjoying the Ambleside Online curriculum (year 1), but I am a secular homeschooler, and I don't share the same moral and religious reasons for homeschooling as the creators and many of the users of AO, I find I have to approach the readings with a little caution. From the beginning, I decided not to do any Bible study. I will let UU Sunday School take care of that (and they are). I researched Trial and Triumph by Hannula, but decided not to use it for a few reasons: I would have had to buy it, as it is not one of the books available for free on the web; it is the history of Christian martyrs which makes the stories intense since every hero dies! Religion is important to history, but I prefer to let my children learn about history and religion through other sources.
Another AO1 resource which I am ambivalent about is Parables from Nature by Margaret Gatty. We read the first story, which has wonderful information about butterflies and a message about trusting that something good comes after death. It is not overtly Christian. The second story I have not yet read aloud. It has wonderful information about bees, but the message has to do with keeping to your station or position in life, and I am uncomfortable with that. I haven't read ahead any further to see what the other stories are like. I haven't included them in our personal schedule -- we may add a few as extras.
Aesop's fables also have moral messages, but I haven't found any of them contrary to my own views. Also, they are so short, that I can easily skim them as I'm settling down to read them aloud. I don't feel I need to prescreen.
Fairy tales can have moral messages, but they can easily be discussed in the context of how one character made choices, or felt pressured, or whatever. They needn't be taken as prescriptive. (Unlike the Gatty parables, which do feel as though they're preaching a universal truth.)
Incidentally, we loved the first fairy tale, Beauty and the Beast, but have been a little disapointed in the others we've read (Why the Sea is Salt, The Glass Slipper, Soria Moria, The Death of Koshchei the Deathless. I think I'll stick to the better known fairy tales for awhile, on the assumption that they are better known because they are better stories!
Those are the books from the Year 1 list that seem to have potentially unwelcome content and messages for non-Christians. I think the others have little Christian content (are the AO advisory board members laughing behind their hands at me?)
I haven't found a mailing list for Non-Christian/Secular AOers, but I'd be interested in other opinions.