It's so sad to see children who thought they knew how to read find out that they can't and need to find a new way to read. This happened to my daughter in first grade. It was challenging teaching her to change her way of reading.
I count six. I could be wrong. (ng is a phonogram)
1. ee
2. ck
3. oo
4. ur
5. ch
6. kn
Mr. Brown Can Moo, Can You? is a book full of common two letter phonograms. My oldest son loved this book. By share reading this book you can teach and have a child practice letter sounds, blends, and common phonograms.
Here's a fun online game to practice common phonograms.
You can find more free online reading games in a link at the top of this blog.