What are the names of long vowel marks?

There isn't a single name for "long vowel marks" because the way long vowels are indicated varies greatly depending on the language and writing system. Here are some examples:

English

* Double vowels: "ee" in "see," "oa" in "boat," "ai" in "rain."

* Single vowels with a mark: "a" in "fate" ("a" with a macron), "i" in "kite" ("i" with a dot above).

Other languages

* Diacritics: Many languages use a variety of diacritics (marks above or below letters) to indicate vowel length. Examples include the acute accent (á), the grave accent (à), the circumflex (â), and the umlaut (ä).

* Double letters: Some languages use doubling of the vowel letter to indicate length (e.g., "aa" in Finnish).

In summary, there is no single, universally applicable name for long vowel marks. The specific mark or combination of marks used to indicate long vowels will depend on the language and writing system in question.