Culinary term for non-flavor defining ingredients In a strongly flavoured soup/stew, curry, or sauce, or salad, you sometimes add other ingredients (eg mixed vegetables) that do not strongly influence the flavor of the end result, but are chosen for color/looks, nutrition, texture or bulk. The flavor/character of the dish itself gets defined/dominated by the spices, aromatics, broths used. They can be, within limits, replaced to make a variation of the same dish. 

Is there a proper term to describe that class of ingredients in a recipe? 

"Toppings" seems to be specific to salad and pizza, AND sometimes refers to something that defines the flavor/character a lot.

"bulk ingredients" is ambigous, could also refer to how they were procured.

"main ingredients" seems ambigous too.

"mixins" sounds too informal.

"garnish" appears specific to things added to the mostly-cooked dish.
I am going to go with ... Drumroll please ... Fillers

credit to my girlfriend who helped me figure out the word I was looking for.

Examples like you stated...starchy root veg in beef stews or the rice in black beans and rice.

Though ingredients used to add color I would really call a garnish even if it's not placed on top of the finished product.