Here is a center you can print on card stock and laminate. Label some clothespins with the numbers 1-20 and the students can match them up.
This is a great way to assess their number sense and number correspondence. I use this during report card testing.
My class loves to do things like this. We count all the time and they ask to do "centers".
If you need certain items, feel free to message me and I will be happy to help.