Here is a simple printable hundred square, in colour or black and white, that can be used for reference, skip counting practice etc.
Simple Hundred Square
Here's a useful pack of hundred squares with a Halloween theme and the times tables 2 through 12 highlighted on each. Laminate them and use them as reference, or put them up as posters perhaps?
There are five hundred squares in this pack to choose from, all requiring children to fill in the blanks. The first and second work on "odds and evens". The third, fourth and fifth drop progressively more numbers from the square for the kids to fill in.