The GMATPREP software contains only 2 CATs and these are the only two CATs that the GMAC provides. However, you may want to take each of these CATs at least twice. Since each of the Verbal and Quant sections in these CATs contains 250 questions, so you are likely to see only a few repeat questions. Some even take these tests thrice as these tests contain retired GMAT questions and are close to what you are likely to see on the GMAT.
Thanks. ANy others? I see that Manhattan has some free CATs. Are they any good?