There are some ingredients that will go into darn near anything. We all know about the basic spices like salt and pepper. Parsley is another of those spices that will add a positive flavor to any dish. My favorite universal ingredient is the carrot, not so much because Bugs Bunny popularized its consumption, but because it adds color and flavor to what otherwise might be some pretty drab dishes. Not that I am into aesthetics or care how stuff looks. As far as I am concerned, all my food could be as brown as mud. Heck, the browner the better. But if you have to please others, wife, kids or even company, it is sometimes best to humor their weaknesses.
If the carrot is the universal vegetable, then the raisin is the universal fruit. It can be tossed into near any sweet dish to make it just a bit more - well - fruity.
As you can imagine, the chicken is the universal meat. It can be substituted for any other meat, with the possible exception of liverwurst for which nothing is the best substitute. After a whiff of liverwurst you won't want to be eating anything anyway.