Are there any tools to detect DHT on a local network? Maybe Kademlia, Hyperswarm or some other library? The goal is not to block DHT (almost impossible), but to write a script or service that will notify if a DHT client is detected on the local network. It is also possible to determine the local ip of the DHT client.
UPD: question about BitTorrent DHT
DHTs are a general concept. Concrete implementations vary wildly, so there's no universal detector for them, especially if they use obfuscation or encryption.
If you're specifically asking about the bittorrent mainline or vuze/biglybt DHTs then, yes, that should be feasible. They're not encrypted so you can implement packet sniffers for them and deploy those on central network components.