Now we move on to the various questions, Magix and Xara are the same program or there are 2 different versions of the program?
Same program. Magix is Xara's parent company.

If I create a graphic with Xara Designer Pro X without using the catalog templates but simply creating a figure I can sell it?
Yes.

What are the limitations of the program?
The only limitations are what you are able to do with the program.

As my goal is to create video game assets and also create my own commercial gaming I wanted to know if there are any restrictions?
None that I am aware of.

Can I sell the images I create with this product?
Yes.