You find many great playlists on the forum that you can import for free without registering on the forum. 
[If you are using an Android emulator, use the Forums window inside iReal Pro or a browser in the emulator. You can use your PC's browser to navigate, search, but you will not be able to import songs into iReal Pro]
 
In iReal Pro, tap on the Forums globe
 
 
Choose from our Essential Playlists: Jazz, Brazilian, Latin, Blues, Pop, Country
Tap/Click Essential Playlists to import them.
 
Here is an example:
 
 
 
You find detailed instructions how to import songs here.
 
 
In case you’re looking for a specific song use the Forum Search.
Tap/Click the Forums (globe icon), then the magnifying glass on the top right and start typing the song title (or band or composer etc.)
 
If you don’t find the song, you can request a song and maybe other iReal Pro users have it and can upload their transcription for you,