i.e. unfollowing people you haven't interacted with or haven't tweeted in years, seeing who unfollowed you, and any other things that would help curate/clean up the timeline more
You don't need a tool for this. Just read your timeline and whenever you see a tweet that is boring or annoying, unfollow the person. If it was a retweet, go turn off the person's retweets. If you want a better timeline, nothing else is necessary or really helpful.