Even within the original scope of the TEI we have

• basic structural and functional components of running text
• diplomatic transcription, images, annotation
• links, correspondence, alignment
• data-like objects such as dates, times, places, persons, events (‘named entity recognition’)
• meta-textual annotations (correction, deletion, etc)
• linguistic analysis at all levels
• contextual metadata of all kinds
• ... and so on and so forth

Is it possible to delimit encyclopaedically all possible kinds of markup?