Adelaide of Italy
Adelaide of Italy (93116 December 999 AD) , also called Adelaide of Burgundy, was a Holy Roman Empress by marriage to Holy Roman Emperor Otto the Great; she was crowned as the Holy Roman Empress with him by Pope John XII in Rome on 2 February 962.
She was regent of the Holy Roman Empire as the guardian of her grandson in 991-995.
Beatrice of Swabia
Beatrice or Beatrix of Swabia( April/ June 1198 – 11 August 1212), a member of the Hohenstaufen dynasty, was Holy Roman Empress and German Queen in 1212 as the first wife of the Welf emperor Otto IV.
She was also the shortest- serving Holy Roman Empress, dying three weeks into her marriage.
Tjuyu
Tjuyu( sometimes transliterated as Thuya or Thuyu) was an Egyptian noblewoman and the mother of queen Tiye, and the wife of Yuya.
She is the grandmother of Akhenaten, and great grandmother of Tutankhamun.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
Eleanor of Portugal, Holy Roman Empress
Eleanor of Portugal (18 September 1434 – 3 September 1467) was Empress of the Holy Roman Empire.
A Portuguese "infanta" (princess), daughter of King Edward of Portugal and his wife Eleanor of Aragon, she was the consort of Holy Roman Emperor Frederick III and the mother of Holy Roman Emperor Maximilian I.
Eleanor of Aragon, Queen of Portugal
Eleanor of Aragon (2 May 1402 – 19 February 1445) was queen consort of Portugal as the spouse of Edward I of Portugal and the regent of Portugal as the guardian of her son.
She was the daughter of Ferdinand I of Aragon and Eleanor of Alburquerque.
Diana Guardato
Diana Guardato was a member of the aristocratic Patrician Guardato family, and had three children with King Ferdinand I: Diana Guardato is the 16th- Great Grandmother of His Royal Highness Albert II of Belgium, 15th- Great Grandmother of His Majesty Juan Carlos
I of Spain, 17th- Great Grandmother of Philippe of Belgium, 14th- Great Grandmother of His Majesty Manuel II of Portugal, 16th- Great Grandmother of Grand Duke Henri, as well as many others.
Hubba bint Hulail
Hubba bint Hulail was the grandmother of Hashim ibn' Abd Manaf, thus the great- great- great- grandmother of the Islamic" Nabī"( Prophet) Muhammad ibn Abdullah.
Elisabeth Christine of Brunswick-Wolfenbüttel
Elisabeth Christine of Brunswick- Wolfenbüttel( 28 August 1691 – 21 December 1750) was Princess of Brunswick- Wolfenbüttel, Holy Roman Empress, German Queen, Queen of Bohemia and Hungary; and Archduchess of Austria by her marriage to Emperor Charles VI.
She was renowned for her delicate beauty and also for being the mother of Empress Maria Theresa.
She was the longest serving Holy Roman Empress.
Maria of Portugal, Duchess of Viseu
Maria of Portugal, Duchess of Viseu (18 June 1521 – 10 October 1577 in Lisbon) was an Infanta of Portugal, the only daughter of King Manuel I of Portugal and Eleanor of Austria.
A noted patron of the arts, Maria's personal wealth rivaled that of the king, her brother (John III of Portugal), making her the richest woman in Portugal and one of the richest in Europe.

Question: Who is Eleanor Of Portugal, Holy Roman Empress's maternal grandmother?
Answer: Eleanor of Alburquerque