The main difference with these worksheets is to keep in mind that you want to make lots of different versions, rather than just one.
Instead of fixed numbers you want to allow a range of possible values, such as integers from -9 to 9 excluding 0 (18 possible values), or 2 decimal numbers from -9.9 to 9.9 excluding all integer values (180 possible values). I usually like to specify a range of "nice" numbers for the answer and let one of the other numbers be the "ugly" one. Besides the obvious esthetic value, nice numbers take up less space on the page and nice answers provide an error check.
Matching is preferable to multiple choice, and long lists are better than short lists. Some random changes are purely cosmetic, but as long as it fools a student peeking at another's work, it has served it's purpose. For example, one could select a random letter to be the variable.
Graphs are easy to generate once I have set up the background grid and labels. 2D geometry diagrams are not that difficult, but 3D perspective diagrams can be time consuming to get right. If you can provide a digitized image, I can probably include it.
I don't always prevent 2 copies of the same question from appearing on a worksheet, as it is statistically unlikely. Also, there is no way to prevent some worksheets from being easier than others, but sometimes there are ways to reduce the problem.
My original plan was to provide OCR grading software, but OCR is neither easy nor cheap.
I lost interest in this project beacuse I could not find any other teachers who thought rampant copying was a problem worth fighting.