I made this last year, but I needed it again today. It's a printable, customized multiplication worksheet for timed tests. It's set out in rows and columns, which you can customize, therefore changing the number of problems. It also allows you to select a range of number for the top and bottom. If you prefer, you can specify the exact numbers you want to choose from.
By default, it produces one hundred questions with both multiplicands between 0 and 9. Thanks to the way it picks, that means each possible problem will appear exactly once.
However, you can also use it to practice difficult numbers. If you have trouble with the fours and sixes, you can specify the top as "4,6", and it will produce 100 problems that include a four or a six.
Use it and have fun!