OS X 10.12 or later. iTunes only allows one playlist to be selected at a time. This applet can perform common useful tasks on a multiple selection of playlists: rename (add text, remove text, search and replace text), duplicate, delete, export, merge.
Tools in the Rename tab operate on the selected playlists' names
(via in-app purchase)
Perhaps Also of Interest...
downloaded 4m 28s ago
Displays files in iTunes Media folder not in iTunes track library
downloaded 14m 39s ago
Display a selected file's audio and Spotlight metadata
downloaded 43m 59s ago
Exports and then re-imports selected tracks' artwork
downloaded 1h 42m 48s ago
Export selected playlists as individual XML or M3U files
downloaded 1h 47m 57s ago
Sort purchased tracks into discrete playlists by name or Apple ID
downloaded 1h 48m 47s ago
Create a playlist of tracks that do not have lyrics text