This is some flowers I found. I found that these were very Autumn-themed because they are orange. I made the oranges in this picture more saturated and I increased shadows to make it sort of black and orange, which are known as Halloween colours.
These are some pumpkins I found while walking around. They fit the autumn theme really well. I didn't do much editing to this, as I really liked the original. So, I cropped it, adjusted white balance, lowered some shadows, and lowered the saturation by a little bit.
This is a picture I took at sunset. For editing, I adjusted lots of the colours to practically change the colour of the sunset. It was bright orange and tea, but I changed it to a purple and orange. Also, I lowered brightness and increased shadows to make a distinct difference between the landscape and the sky.