Thanksgiving/Christmas/New Year's.
You missed a few, just in December. From the website/page
https://www.brownielocks.com/december.html:
December 2020 Daily Holidays
*Antartica Day: 1
*Basketball Day: 1
*Bifocals at the Monitor Liberation Day: 1
*Civil Air Patrol Day: 1
*Clark Kent's Birthday (Superman): 1 Link (Note: Also June 18 in another Comic)
*Day With(out) Art Day: 1
Giving Tuesday: 1 Link (The day after Cyber Monday)
*Rosa Parks Day: 1
*World Aids Day: 1 Link
World Trick Shot Day: 1 (First Tuesday)
*International Day for the Abolition of Slavery Day: 2
*National Mutt Day: 2 Link (Also July 31 every year)
National Package Protection Day: 2 Link (Following Wednesday after Thanksgiving)
Rockerfeller Christmas Tree Lighting: 2 ?
*Safety Razor Day: 2
*Special Education Day: 2
Special Kids Day: 2 Link (First Wednesday)
*Be A Blessing Day: 3
*E-Discovery Day: 3
*International Day of Persons With Disabilities: 3
Faux Fur Friday: 4 (First Friday)
*National Cookie Day: 4 Link
*National Dice Day: 4
National Salesperson Day: 4 (First Friday)
*National Sock Day: 4 Link
*World Wildlife Conservation Day: 4 Link
*AFL-CIO Day: 5
Bartender Appreciation Day: 5 Link Link (First Saturday) Note: Feb. 24 is World Bartender Day.
*Bathtub Party Day: 5
Bike Shop Day: 5 (First Saturday)
*Columbian International Day of The Reef: 5 Link
Earmuff Day or Chester Greenwood Day: 5 Link (First Saturday)
*International Ninja Day: 5 Link Photo Photo
*International Volunteer Day for Economic & Social Development: 5
National Play Outside Day: 5 Link (First Saturday)
National Rhubarb Vodka Day: 5 Link (First Saturday)
Skywarn Recognition Day: 5 Link (First Saturday)
World Pear Day: 5 Link (First Saturday)
*Sachertorte Day: 5 Link
*World Soil Day: 5 Link
*Miners' Day: 6
*Mitten Tree Day: 6 Link
*National Pawnbrokers Day: 6
*St. Nicholas Day: 6
*International Civil Aviation Day: 7
*National Cotton Candy Day: 7 Link
*National Pearl Harbor Remembrance Day: 7
*AFL-CIO Day: 8
*Bodhi Day: 8 Link [Traditional] (See also Jan. 5)
*National Day of Lard: 8
*Pretend To Be A Time Traveler Day: 8
*Toilet Paper Appreciation Day: 8 Link
*Cremation Day: 9
*International Anti-corruption Day: 9
*International Day of Commemoration and Dignity of The Victims of The Crime of Genocide and The Prevention of This Crime: 9
*Weary Willie Day: 9 Link
*World Techno Day: 9 Link
Chanukah: 10 (at Sundown)
*Dewey Decimal System Day: 10
*Human Rights Day: 10 Link
*International Animal Rights Day: 10 Link
*Jane Addams Day: 10
*Nobel Prize Day: 10
*International Mountain Day: 11
*Kaleidoscope Day: 11
*Magnum P.I. Day: 11
*National App Day: 11 Link
National Salesperson Day: 11 (2nd Friday) (Also in March)
*National Sobriety Day: 11 Link
Official Lost & Found Day: 11 (2nd Friday)
*UNICEF Birthday: 11
Day Of The Horse: 12 (Always 2nd Saturday Senate Res. 452)
Gingerbread Decorating Day: 12 (2nd Saturday)
Gingerbread House Day: 12 (Second Saturday)
*International Day of Neutrality: 12
International Shareware Day: 12 (2nd Saturday)
*International Universal Health Coverage Day: 12
*National 12-hour Fresh Breath Day: 12
*National Ding-a-Ling Day: 12 Link
*National Cocoa Day: 12 Link
*National Lost Day: 12 Link
*Our Lady of Guadelupe: 12 Link
*Poinsettia Day: 12
National Day of The Horse: 12 Link (Second Saturday)
National Wreaths Across America Day: 12 (2nd Saturday) Link
International Mobile Phone Recycling Day: 13? Link (Moved from January)
*National Guard Birthday: 13 Link
Worldwide Candle Lighting Day (The Compassionate Friends): 13 Link (The 2nd Sunday)
World Choral Day: 13 Link (Always 2nd Sunday)
AKC Champtionships: 14
Green Monday: 14 Link (2nd Monday)
*Monkey Day: 14 Link or Link
*Yoga Day: 14 Link
*Bill of Rights Day: 15
*Cat Herders Day: 15 Link
*International Tea Day: 15 Link
*National Cupcake Day: 15
*National Wear Your Pearls Day: 15 Link
*Zamenhof Day (Esperato Literature Day): 15 Link
*Barbie and Barney Backlash Day: 16
*National Chocolate-covered Anything Day: 16 Link
*Zionism Day: 16
*A Christmas Carol Day (Story): 17
*Clean Air Day: 17
Free Shipping Day: 17 Link (3rd Thursday at Participating Retailers)
National Re-gifting Day: 17 (3d Thursday) Link
*Wright Brothers Day: 17
*Answer The Telephone Like Buddy The Elf Day: 18 Link
*Arabic Language Day: 18 Link
*Give A Wine Club Day: 18 Link
*International Migrants Day: 18
Underdog Day: 18 (3rd Friday)
*Games Day: 20 Link
*International Human Solidarity Day: 20
*Mudd Day: 20
*National Sangria Day: 20
*Poet Laureat Day: 20
*World Day of Prayer and Action for Children: 20 Link
*Ann & Samantha Day: 21 (Summer & Winter Solstices. Also June 21) Link
*Celebrate Short Fiction Day: 21 (Always on Winter Solstice)
*Crossword Puzzle Day: 21
*Forefathers Day: 21
*Global Orgasm Day: 21 Link (Always on Winter Solstice and Summer Solstice)
*Humbug Day: 21
*International Dalek Remembrance Day: 21 Link
*Make Music Day in Winter: 21 Link (Note: Also on June 21)
*National Flashlight Day: 21 (Shortest Day of The Year)
*National Homeless Persons' Remembrance Day: 21 Link
*Phileas Fogg Win A Wager Day: 21
*Short Girl Appreciation Day: 21 (Shortest day of the year)
*Shorts Day: 21 (On Winter Solstice)
*World Peace Day/Winter Solstice: 21
Winter (Winter Solstice): 21 5:02 AM EST
*Yalda: 21
*Yule: 21
*Be A Lover of Silence Day: 22
Chanukah: 22-30
*Forefathers Day: 22 Link
*Family Roots Day: 23 Link
*Festivus: 23
*Human Light Celebration: 23
*Metric Conversion Day: 23
*Christmas Eve: 24
*Egg Nog Day:24 Link
*A'Phabet Day or No "L" Day : 25
Asarah B'Tevet: 25
*Christmas: 25
*Christmas Pudding Day: 25 Link (Note: If you eat this on Easter, it's referred to as Plum Pudding Day.)
National Ugly Christmas Sweater Day: 25 Link (Friday of Third full week)
*Boxing Day: 26 (Canada)
*Kwanzaa: 26-1/1
*National Candy Cane Day: 26 Link
*National Thank-you Note Day: 26
*National Whiner's Day: 26
*Free Balloon Day: 27 Link (SpongeBob Squarepants)
*Howdy Doody Day: 27
*Radio City Music Hall Day: 27
*Visit The Zoo Day: 27 Link
*Holy Innocents Day: 28
*Endangered Species Act Day: 28
*National Chocolate Day: 28-29 Link
*Pledge of Allegiance Day: 28
*Short Film Day: 28 Link
*Tick Tock Day: 29
*YMCA Day: 29 (Organization not The Song)
*Bacon Day: 30 Link Link
*Falling Needles Family Fest Day: 30
*First Nights: 31
*Hogmanay: 31 Link
*Leap Second Time Adjustment Day: 31
(Note: This is listed as an observance title only. Some years scientists do not make adjustments.
But, if they do, then it's done on either June 30 or December 31.)
*Look On The Bright Side Day: 31 Link
(Note: It can be any day. But, I posted it here to start the next year off positive and happy.)
*Make Up Your Mind Day: 31
*National Champagne Day: 31 (Note: US Champagne Bureau has another observance on Oct. 28)
*New Years Eve: 31
*New Year's Eve Banished Words List: 31
*New Year's Dishonor List: 31
No Interruptions Day: 31 (Last Business Day of The Year)
*Universal Hour of Peace Day: 31
*World Healing Day: 31 Link Note: Different than one on April 29.
*World Peace Meditation Day: 31
