Categorizing Foods By Color

Do you mean yellow fruits & veggies mostly...like in "eating the rainbow" for health reasons? (they usually lump yellow & orange together)

http://www.ag.ndsu.edu/pubs/yf/foods/fn595w.htm#reasons

and:
Rainier cherries
Yellow wax beans

If you are looking for yellow food of any kind for a theme type party...then:

Banana (skin) or banana Popsicle
Yellow popcorn (or buttered)
yellow lentils , and some grains
various yellow candy (candy corn, lemon drops, yellow m&m's...)
Mt Dew soda, lemonade, eggnog
butter/margarine & some cheeses
mustard & some other condiments
some cakes & cookies & puddings
egg bread, egg noodles
egg yolks / scrambled egg dishes
polenta, grits, corn chips, tortilla chips
yellow rice or dishes with turmeric, etc.