I simply Googled "free IELTS exercises" and found 1300 pages. Of course, there is no guarantee that they are all top quality but I think if you want to do as many exercises as possible, then this is a good way to start.
Hint: If you are searching on the net for things like this, use "exercises", not "samples". We don't really use the word "samples" in this context.
- For Teachers