libmwaw contains some import filters for old Macintosh text documents (MacWrite, ClarisWorks, ... ) and for some graphic and spreadsheet documents. It is based on top of the librevenge (see https://sourceforge.net/p/libwpd/wiki/librevenge/ ).
Currently, libmwaw is a new project, but it tries to import with some success about forty different formats (see the Wiki section for more details).