Basically, I know that abstract base classes are used as skeleton classes just like regular classes, and there main advantage would be to enforce their implementation on the child classes.
But I was wondering if I have the next case:
I have a class which is having only static methods / no init -> it would make sense to make it abstract? It would be pythonic?
I was thinking the advantage would be that some one reading the code would know that that class should not be instantiated...
It seems that you're trying to emulate namespaces. It's better to use modules. The mechanism is built into Python, and functions as a namespace:
https://docs.python.org/3/tutorial/modules.html
An abstract class with only static-methods can work as a namespace, but it's confusing to people reading the source code