Bitmagnet is a self hosted bittorrent DHT crawler/database. Basically a self hosted meta search engine for torrents, like Knaben or ext.to.
Bittorrent has for ages had a decentralized network to find additional peers outside of the trackers listed in your torrent file/magnet link. Bitmagnet crawls this network grabbing hashes from everything it finds and puts it in a postgres database. It also has a classifier that allows you to tag and prevent adding torrents based on string matching and TMDB id numbers.
I just got it setup before bed and woke up to it already having 120k files logged. It's neat to look at what other people are downloading, especially given how many torrents are hidden behind private trackers these days. Just browsing what I've crawled overnight I see one TV show that I could not find on the public torrent sites.
It has a servarr integration, so it easily plugs into prowlarr/sonarr/radarr, etc.
If you're going to try it, here's a few tips:
Definitely set a scaling factor or it'll use a low of resources and bog your system down. I started with a scaling factor of 3, which seems fine resource wise.
Make sure you have enough storage space, it apparently consumes a lot of space right away, but less and less over time as your database ends up already having the vast majority of active torrent hashes. I'm seeing people reporting 100gb after many months of running, which isn't that bad, IMO.
Run it through a VPN/wireguard that is outside your home network. Not for copyright purposes(it's not downloading anything), but because it spawns a ton of connections, enough to smoke most home routers.
Here's a docker compose file I found that was helpful. Just change the gluetun settings to whatever VPN you have and change the volume mounts to wherever you have the storage space.
https://pastebin.com/RCEbZQd2