Sonarr, Radarr, qBitorrent, SabNzbd, Jackett and frontends like Kodi and Jellyfin. Jackett can interrogate a whole bunch of public and private torrent trackers for you, fetch a .torrent file given a set of criteria (like are there seeders) and put it in your torrent client for you. It does all this automatically from Sonarr/Radarr once set up in them.

I set all this up in my server using my phone and an Android SSH client from my bed while recovering from nasty painful surgery and it’s been pretty solid once I worked out the kinks since.