I never use almond flour lately and have gotten in the habit of using pecan flour quite a bit. (it does taste a little more pecan ish then of course). I have also used walnuts and peanut flour but those just didn't have a great taste.

Also for lc crackers I have used ground sunflower seeds which worked quite nicely as well!!

Hazelnuts though, like Rosebud suggested, have a nice neutral flavor as well!