A new Wget (Wget2) already has feature:
--filter-mime-type Specify a list of mime types to be saved or ignored`
Specify a comma-separated list of MIME types that will be downloaded. Elements of list may contain wildcards.
If a MIME type starts with the character '!' it won't be downloaded, this is useful when trying to download
something with exceptions. For example, download everything except images:
wget2 -r https://<site>/<document> --filter-mime-type=*,\!image/*
It is also useful to download files that are compatible with an application of your system. For instance,
download every file that is compatible with LibreOffice Writer from a website using the recursive mode:
wget2 -r https://<site>/<document> --filter-mime-type=$(sed -r '/^MimeType=/!d;s/^MimeType=//;s/;/,/g' /usr/share/applications/libreoffice-writer.desktop)
Wget2 has not been released as of today, but will be soon. Debian unstable already has an alpha version shipped.
Look at https://gitlab.com/gnuwget/wget2 for more info. You can post questions/comments directly to firstname.lastname@example.org.