Chop the eggs and potatoes to the sizes you like and put them in a large bowl with the cooked onion and mix.In another bowl mix together mayo, ranch, relish (pickles), mustard, salt, pepper, paprika, and celery seed.Pour the the mayo/ranch/spices mix in with the eggs and potatoes and mix to combine.Right before you serve it mix in the bacon. This will ensure the bacon is still crispy.