torrents-csv.ml is excellent. It’s a compiled database of other torrent sites that is pruned of unseeded torrents. It usually has what I need except for new releases, as they aren’t added immediately.
Side note: Jackett is nice but Prowlarr is better. Jackett development has stopped. Prowlarr is a little bit more feature rich and can automatically add indexers to Sonarr and Radarr.