For that matter is a common phrase used to introduce something related to the topic being discussed. However, it is always great to have a variety of synonyms to avoid repetition. Here are some alternatives to consider: in fact, as a matter of fact, to be precise, to be exact, actually, in reality, in truth, moreover, furthermore, not to mention, to say nothing of, and last but not least. By using these phrases interchangeably, you will be able to spice up your writing and maintain the reader's interest. Nonetheless, do not overuse them, as it could make your writing sound unnatural.