When there's a top post in r/listentothis, it'll automatically be added to a Spotify playlist for you.
If
New top post in subreddit
This Trigger fires every time a new post becomes one of the ten top posts in the subreddit you specify.
Then
Add track to a playlist
This Action will search for a track and add the first result to a playlist you specify.
Explore more great ways to automate Spotify and Reddit