wordpress-mime-type-upload-disable.php

/**
* Add that code to your theme functions.php file. Choose or modify which file/mime type need and delete the others.
* Replace the file type. More info: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
* Gist by Tamas Rottenbacher
* Source: https://wpsmackdown.com/add-remove-filetypes-wordpress-media-library/
*/
function disable_mime_types($mime_types){
    unset($mime_types['bmp']);      // Disable .bmp file upload
    unset($mime_types['tiff']);     // Disable .tiff file upload
    return $mime_types;
}

add_filter('upload_mimes', 'disable_mime_types', 1, 1);