From the former Wikipedia page [1] which was classified as a stub, and had had an improvement tag since October 2009, and is now part of the article on Asemic writing. It provides links to the various texts mentioned (and several of which are covered on the other Voynich Manuscript wiki [2])

False writing systems are artificially constructed alphabets or scripts used (sometimes within the context of a false document) to convey a degree of concealed verisimilitude. Examples of this include alien dialogue in comic strips and graphic novels (such as Alan Moore's The League of Extraordinary Gentlemen [3], and the Valérian and Laureline series [4]). The script in Luigi Serafini's 1981 Codex Seraphinianus [5] may be a false writing system; so perhaps may be the text of the Voynich manuscript.

See also the Wikipedia page on fictional languages [6].