Here is a set of mats for the short o word families. It includes -og, -op, and -ot. You can cut out the letters provided and have kids spell the words, or you can write the letters on inch tiles or water bottle caps for easier manipulation and more fun. Just print and laminate for a quick and easy literacy center.
You can get this in a bundle with the other short vowels at a really discounted rate here:
Word Family Mat Short Vowel Bundle