public FieldFactory[] getUnusedFactories() {
		List<FieldFactory> list = new ArrayList<>(Arrays.asList(factories));
		for (int i = 0; i < rows.size(); i++) {
			Row row = rows.get(i);
			FieldFactory[] rowFactorys = row.getFactorys();
			for (FieldFactory rowFactory : rowFactorys) {
				Class<?> c = rowFactory.getClass();
				for (int k = 0; k < list.size(); k++) {
					if (c.equals(list.get(k).getClass())) {
						list.remove(k);
						break;
					}
				}
			}
		}
		return list.toArray(new FieldFactory[list.size()]);
	}
Returns a list of unused valid fields for this model 
@return a list of unused valid fields for this model
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/format/FieldFormatModel.java