how many methods available for preparing Income statements?
I know two methods, Absorption costing and variable costing methods, the first one is required by GAAP, the second one is for internal use and making decisions.
is there any other method to prepare Income statements?

Yes and no. There aren't any specific "rules" in cost accounting about how things have to be done. A manager wants certain information, presented in a certain way, and that's what you do. (Though it should, of course, make some sort of sense and be useful.) From that point of view, you can do whatever you want.

But in the context of what you're doing, in terms of what is "typical," no.