Sleeker, supports file drag and drop, with a very quick and simple way to add common metadata across many files.
SearchKey
How to use extended attributes and SearchKey to find the right file(s) first time, every time. Includes new beta-release.
New batch file mode can add (e.g.) copyright metadata to hundreds or thousands of files. Handles unusual characters properly. Can also remove extended attributes.
Adds keywords, author, copyright and other info to any file on your Mac. Runs in El Capitan, Sierra, and High Sierra.