One thing I added is multiplication facts around my door frame and window frame. I just used paint samples and had the students help me write "tricky" multiplication facts. This allows kids to be exposed to their multiplication facts and it is a reference point, especially if they don't know all of their multiplication facts.
I also have a vocabulary corner for the vocabulary words for the chapter.
The Ladybug Teacher Files. They are great... and FREE!!!!
One of my FAVORITE things I have in my classroom is a multiples number line. I bought this at a Kim Sutton training. If you ever have the opportunity to go to a training, I highly recommend it. She gives a lot of great ideas and creative ways for kids to practice math. My school has all of her math game books in the library and they are wonderful!
There are some freebies, you just have to click around the site to find them.
One last thing that I have in my classroom is math reference books. My students have been writing their own math reference book. They use a composition notebook and include a table of contents, page numbers, and helpful information on each page. I do not have pictures yet, but I will add them soon!!!