Thunar OpenDocument Thumbnailer
Simple way
/usr/share/thumbnailers/thunar-vfs-font-thumbnailer-1.desktop
[Desktop Entry] Version=1.0 Encoding=UTF-8 Type=X-Thumbnailer Name=OpenDocument Thumbnailer TryExec=/usr/lib/thunar/thunar-vfs-odf-thumbnailer-1 MimeType=application/vnd.oasis.opendocument.presentation;application/vnd.oasis.opendocument.presentation-template;application/vnd.oasis.opendocument.spreadsheet;application/vnd.oasis.opendocument.spreadsheet-template;application/vnd.oasis.opendocument.text;application/vnd.oasis.opendocument.text-template;application/vnd.oasis.opendocument.graphics;application/vnd.oasis.opendocument.graphics-template; X-Thumbnailer-Exec=/usr/lib/thunar/thunar-vfs-odf-thumbnailer-1 %i %o
/usr/lib/thunar/thunar-vfs-odf-thumbnailer-1