Trader Joe's has several with out cross contamination. We have used them for my daughter's food challenges;

I have a peanut allergy and respond to almonds due to oral allergy syndrome. My allergist advised me to avoid all nuts in order to eliminate the possibility of cross contamination. I've lived my life strictly avoiding all nuts. Good Luck

twinspringspecans.com
just processes pecans, no other nuts.

I have a severe peanut allergy but no tree nut allergies & Blue Diamond brand almond products are peanut free and safe. Wonderful brand tree nuts are also safe. I believe the larger size bags are available at Costco!

I agree it can be very difficult. I have a peanut allergy, but ice come to notice that health food stores and places like trader Joe's has products not processed around them. I replaced peanut butter with their sunflower seed butter. Yumm