Is there a keyboard shortcut to navigate full screen windows of the same application?
Solution 1:
Try Contexts for Mac. I replaced the built-in apps switcher with this utility which lets me to view full screen windows including a feature to search active windows by title.
Solution 2:
Witch also includes full screen windows, and ⌥⇥ selects the next window from the current application by default.
Or if you use an application that has its own implementation for full screen windows (like WriteRoom), ⌘` usually includes custom full screen windows.