The pickle relish is often described as the thing that defines Thousand Island ... the idea that Russian dressing originally included caviar, and there are 1950s-era recipes for Russian dressing ...
Thousand Island Sauce is frequently used as a dressing for salads. It is made with mayonnaise, chilli powder and tomato ketchup. Egg and celery are added in this recipe to give some flavor.
In fact, homemade creamy, tangy thousand island dressing is just a blend ... may be more your style. Many recipes call for pickle juice, but relish is a great stand-in; Just mix the dressing ...