It would be very useful to be able to insert a special character (similar to the "current page number" marker) that makes a digit counter, starting with 1 and then iterating upwards for each time it's inserted.

I know there's a workaround to sort of do this with numbered lists, but that's very limited, especially if you want the counter anywhere except the beginning of a paragraph.

I'm currently working a book that has many images with captions, that ends with the number of the image, like this: "Lorem ipsum dolor… [15]". If "15" where a simple character that counted upwards that would make it so much easier in case the pages get moved around.