Question: What is this grapheme still in use as a letter in some languages, including Danish, Norwegian, and Icelandic that the Old English Latin alphabet had?

Context articles: Western Latin character sets (computing)
Æ
Somali Latin alphabet
Latin alphabet
ANSEL
E
Glottal stop (letter)
C
Filipino alphabet
Old English Latin alphabet

Several binary representations of character sets for common Western European languages are compared in this article.
 These encodings were designed for representation of Italian, Spanish, Portuguese, French, German, Dutch, English, Danish, Swedish, Norwegian, and Icelandic, which use the Latin alphabet, a few additional letters and ones with precomposed diacritics, some punctuation, and various symbols (including some Greek letters).
 Although they're called "Western European" many of these languages are spoken all over the world.
 Also, these character sets happen to support many other languages such as Malay, Swahili, and Classical Latin.
Æ (minuscule: æ) is a grapheme named æsc or ash, formed from the letters "a" and "e", originally a ligature representing the Latin diphthong "ae".
 It has been promoted to the full status of a letter in the alphabets of some languages, including Danish, Norwegian, Icelandic, and Faroese.
 As a letter of the Old English Latin alphabet, it was called "æsc" ("ash tree") after the Anglo-Saxon futhorc rune ᚫ () which it transliterated; its traditional name in English is still ash .
 It was also used in Old Swedish before being changed to ä.
 Variants include Ǣ ǣ Ǽ ǽ æ̀.
The Somali Latin alphabet is an official writing script in the Federal Republic of Somalia and its constituent Federal Member States.
 It was developed by the Somali linguist Shire Jama Ahmed specifically for transcribing the Somali language, and is based on the Latin script.
 The Somali Latin alphabet uses all letters of the English Latin alphabet except "p", "v" and "z".
 There are no diacritics or other special characters, although it includes three consonant digraphs: DH, KH and SH.
 Tone is not marked and a word-initial glottal stop is also not shown.
 Capital letters are used for names and at the beginning of a sentence.
The classical Latin alphabet, also known as the Roman alphabet, is a writing system originally used by the ancient Romans to write the Latin language.
 The Latin alphabet evolved from the visually similar Cumaean Greek version of the Greek alphabet, which was itself descended from the Phoenician abjad, which in turn was derived from Egyptian hieroglyphics.
 The Etruscans who ruled early Rome adopted the Cumaean Greek alphabet which was modified over time to become the Etruscan alphabet, which was in turn adopted and further modified by the Romans to produce the Latin alphabet.
ANSEL, the American National Standard for Extended Latin Alphabet Coded Character Set for Bibliographic Use, was a character set used in text encoding.
 It provided a table of coded values for the representation of characters of the extended Latin alphabet in machine-readable form for thirty-five languages written in the Latin alphabet and for fifty-one romanized languages.
 The standard was reaffirmed in 2003 although it has been administratively withdrawn by ANSI effective 14 February 2013.
 It is registered as Registration # 231 in the ISO International Register of Coded Character Sets to be Used with Escape Sequences.
E (named "e" , plural "ees") is the fifth letter and the second vowel in the modern English alphabet and the ISO basic Latin alphabet.
 It is the most commonly used letter in many languages, including Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Latvian, Norwegian, Spanish, and Swedish.
The sign ⟨ʔ⟩ is called "glottal stop" and it is a letter in some extended Latin alphabets of several languages of Canada.
 It is not part of the basic Latin alphabet or Classical Latin alphabet.
 Several phonetic transcription schemes, such as the International Phonetic Alphabet (IPA), use versions of glottal stop.
C is the third letter in the English alphabet and a letter of the alphabets of many other writing systems which inherited it from the Latin alphabet.
 It is also the third letter of the ISO basic Latin alphabet.
 It is named "cee" (pronounced ) in English.
The Modern Filipino alphabet (Filipino: "Makabagong alpabetong Filipino" ), otherwise known as the Filipino alphabet (Filipino: "alpabetong Filipino" ), is the alphabet of the Filipino language, the official national language and one of the two official languages of the Philippines.
 The Modern Filipino alphabet is made up of 28 letters, which includes the entire 26-letter set of the ISO basic Latin alphabet, the Spanish "Ñ" and the "Ng" digraph of Tagalog.
 It replaced the Pilipino alphabet of the Fourth Republic.
 Today, the Modern Filipino alphabet may also be used as the alphabet for all autochthonous languages of the Philippines and in writing Chavacano, a Spanish-derived creole.
The Old English Latin alphabet—though it had no standard orthography—generally consisted of 24 letters, and was used for writing Old English from the 9th to the 12th centuries.
 Of these letters, 20 were directly adopted from the Latin alphabet, two were modified Latin letters (Æ, Ð), and two developed from the runic alphabet (Ƿ, Þ).
 The letters K, Q and Z were not in the spelling of native English words.