[napsterbr]

Another interesting self-hosted tracker is https://ryot.io/.

Demo: https://demo.ryot.io/_s/acl_vUMPnPirkHlT

Code: https://github.com/IgnisDa/ryot

(PS: they opted to go in a direction where it also includes some media-related features -- like tracking movies or books you've seen/read -- but this can be disabled).