TwitterAudit is a good service for finding and monitoring fake and bot accounts following you on Twitter. It's got detailed statistics, including follower audits, engagement metrics and growth graphs. That can help you keep a real and engaged audience, so your Twitter presence is credible and useful.
Another option is Followerwonk, a set of AI-infused Twitter analytics tools. You can use it to analyze your followers by location, bio and the accounts they follow. You can also use it to optimize your activity, track engagement and forecast the results of your tweets. That can help you tune your social media strategy and figure out who's actually paying attention to your tweets.
If you want to take a more community-oriented approach, Hive can help you find and manage accounts you can trust by monitoring communities and ranking influential accounts. It's got features like visual community membership, community rankings and bulk account management, so you can better manage and engage with your Twitter contacts.