When you're looking to express that you need something more, there are several synonyms for "demand additionally" that you can use. For instance, you could use "furthermore," "moreover," "in addition," or "additionally" itself to indicate that you need something else to be included. Similarly, "besides," "even more," "plus," and "on top of that" are all synonyms that indicate that you require more than what has already been given. Additionally, "not to mention" can be used to imply that something else must be taken into account, while "as well as" or "along with" indicate that you need specific items added to what has already been provided. Overall, there are many ways to express that you require more, depending on the context of the situation.