are there any other spices or food to use instead of “prepared horseradish”?

It would help to know what you’re making. If it’s a dip, here’s a pretty good one:
1/4 to 1/2 lb. smoked salmon
2 (8-oz.) pkgs. cream cheese
1 c. finely chopped red onion
1/4 cup chopped fresh parsley
Cracked black pepper

Remove dark tissue along line of fish and crumble into small bits. Combine fish, cream cheese, onion and parsley in a bowl; mix until you reach a firm, even texture. Form into a ball and generously sprinkle fresh black pepper all over.

And, here’s another good smoked salmon dip without horseradish:
8 oz. whipped cream cheese, softened
1/2 cup sour cream
8 oz. smoked salmon
Dash of lemon juice or lemon zest
4 Tbsp. fresh chopped chives (you can use 2 Tbsp. of chopped fresh dill instead if you wish)

Mix all ingredients and store in the fridge for a few hours to let flavors develop. Let come to room temperature before serving. If making this a day ahead, mix all ingredients except the chives or dill– add them right before serving instead. Serve with your favorite buttery crackers.