PrivTracker allows to share torrent files just with your friends, nobody else.
Unlike public trackers, it shares peers only within a group which is using the same Announce URL.
It really works like a private tracker, but can be generated with one click of a button.
Your announce URL:
https://privtracker.com/{{room}}/announce
(You can also use any random string as the Room ID. We don't store it anywhere.)