September 1st: National Ginger Cat Appreciation Day
September 2nd: National Lazy Mom’s Day
September 3rd: International Bacon Day
September 4th: National Pet Rock Day
September 5th: National Be Late for Something Day
September 6th: National Read a Book Day
September 7th: National Acorn Squash Day
September 8th: National Iguana Awareness Day
September 9th: National When Pigs Fly Day
September 10th: National TV Dinner Day
September 11th: Hug Your Hound Day
September 12th: National Chocolate Milkshake Day
September 13th: National Kids Take Over the Kitchen Day
September 14th: National Cream Filled Donut Day
September 15th: National Double Cheeseburger Day
September 16th: National Guacamole Day
September 17th: International Eat An Apple Day
September 18th: International Red Panda Day
September 19th: Talk Like a Pirate Day
September 20th: National String Cheese Day
September 21st: International Day of Peace
September 22nd: National Elephant Appreciation Day
September 23rd: Hug A Vegetarian Day
September 24th: National Punctuation Day
September 25th: National Roadkill Day
September 26th: Alpaca Day
September 27th: National Crush A Can Day
September 28th: Ask a Stupid Question Day
September 29th: National Starbucks Day
September 30th: Extra Virgin Olive Oil Day

Cites: https://nationaltoday.com/september-holidays/
https://www.shutterstock.com/search/september