Different colored construction paper cut in small pieces (if you did the activity 'scissors anyone' your pieces are ready for use!)
Tell your child that you are going to try to make a secret pattern and then try to guess each others pattern! Model how to make it by showing an example. "I'm going to use red, red, yellow, blue. Red, red, yellow, blue. " Then put another red at the end and ask " can you guess what goes next on my secret pattern?" If the child has a hard time say the colors again slowly and rhythmically to help. If this pattern is still complicated don't stress over it. Give them the answer and then try a simpler pattern! Keep practicing and they will get better and better.
If you have school age children they have probably worked on patterns at school. Ask them to solve the pattern using letters or numbers instead of saying the colors. There's a sample pattern my 8-year-old made using the letters. You can make it more challenging by adding colors or making more complex combinations for your patterns.