UPDATED: Append to Selected Tag v5.2
For macOS 10.15 Catalina and later. Append the same user-entered text to the beginning or ending of the existing text in the chosen tag--Title, Artist, Album Artist, Album, Composer, Comments, Genre, Grouping, Show (or their Sort siblings), Work or Movement--in each selected track.
Latest version:
- UI update/clean-up, maintenance, minor fixes
More information for Append to Selected Tag v5.2 and download link is here.