In principle, one could combine any two or more hops, but one may want to exercise caution. In general, there are many Wizards who advise against combining British or Noble hops with one of the four C’s, for example. You can always do a Google search to see if has been attempted.

British hops:  Many British hops are known to combine well. For example, Fuggle, East Kent Golding, Challenger, Target and Northdown hops can be mixed to make a good English ale.

Noble/Continental hops: Saaz hops, with their spicy aromas from their Czeck origins work with almost any home brew. Spalt, Tettnanger, and Hallertau Mittelfrüh are other varieties that mix well.

American hops: The “four Cs” are very popular for their fruity flavors and they are popular for brewing wizards because of their symbiotic properties. Each has its own bouquet that contributes to the citrusy taste of pale ales. Willamette, U.S. Fuggle, Yakima Golding, and Mt. Hood are other American hops that combine well together.