The list of options for transformations is the following: w_ and h_ are the dimensions of your file, c_ is for cropping, wm_ shows if you have a watermark and q_ stands for quality adjustment.
In the Top options section, you'll be able to see a list of the options that are shown most often to your users. The numbers in parenthesis represent the number of requests for that specific option, and its percentage in regards to other requests, respectively.
Still unsure what options and transformations are? Take a look at our documentation for an in-depth explanation.