Reformation Day

Reformation Day (Slovenia, parts of Germany, Chile, various Protestant churches with a particular emphasis in Lutheran and Reformed ones)

National Unity Day (India)

National Unity Day (India)

Public holidays in Cambodia

King Father's Birthday (Cambodia)

Scouts' Day

Girl Scouts Founders Day (United States)

Day of the Dead

Halloween and related celebrations:
The first day of the Day of the Dead, celebrated until November 2 (Mexico)

Samhain

Halloween and related celebrations:
Samhain in the Northern Hemisphere, Beltane in the Southern Hemisphere; begins on sunset of October 31 (Gaels, Welsh people and Neopagan Wheel of the Year)

Hop-tu-Naa

Halloween and related celebrations:
Hop-tu-Naa (Isle of Man)

Halloween

Halloween and related celebrations:
Halloween (Ireland, Canada, United Kingdom, United States and other places)

Allantide

Halloween and related celebrations:
Allantide (Cornwall)

All Saints' Day

Earliest day on which All Saints Day can fall, while November 6 is the latest; celebrated on Saturday between October 31 and November 6 (Finland, Sweden)

Día de la Canción Criolla

Día de la Canción Criolla (Peru)

October 31 (Eastern Orthodox liturgics)

Christian feast day:
October 31 (Eastern Orthodox liturgics)

Wolfgang of Regensburg

Christian feast day:
Wolfgang of Regensburg

Theodore Romzha

Christian feast day:
Blessed Theodore Romzha (Ruthenian Catholic Church)

Saint Quentin

Christian feast day:
Quentin