Leaves

As you can see, we incorporate a lot of leaves into our Fall seasonal crafts, but you can just as easily make whatever you like as the "extra finishing touch".
Flowers are good on wreaths and such, and berries (like kernels) are easy and quick color to a project. Sometimes they can get messy, though, so honestly, you can do just about anything you need to make your projects stand out.

We have many fake leaves to use, so we make Fall crafts from them usually...