I do have some stencils (I long arm) but find that I don't use them as much as free motion or ruler work. Why? Well, it takes a lot of time to mark the stencils--plus then you have to get the markings off--which when I do use stencils I will use either chalk, the F & P ceramic pencil (LOVE this), or a blue or purple water soluble pen (don't use these on customer quilts unless we've talked about it first as they HAVE to completely immerse to make sure it gets out of bat and back, not just top). also, it seems like lots of stencils are made for handquilters or are at least not continuous, which is what is preferable with long arm quilting. What I do use often is Pam Clarke's (and similar) stencils that give registration markings to use with FMQ or ruler work.
I've found good stencils at the Stencil Co. booth at several shows--check out their website. If you still don't find what you want, just google stencils and long arm quilting supplies.