What exactly are you looking for -- the playlist name itself or a song within the playlists?
Rekordbox 5 - search playlists
I have about 200+ playlists all for different occasions, would it be able to add a search bar below "Playlists" in the left sidebar? It gets kind of hard scrolling through them all searching for the correct playlist.
The playlist name itself - it' would be good when you have a naming system for your playlists to be able to search them by name :)
Currently, if you set the focus to the left tree and type any letter, it will jump to the first section or playlist starting with that letter. Press it again to move to the next one. It's not the search you're looking for (as typing the second letter makes it jump to the first item starting with THAT letter), but it could be a bit of a work-around as this suggestion is in consideration.