Yes, there are compiled tor relay packages for BSD, they exist in packages - for FreeBSD is pkg install tor and for OpenBSD it’s pkg_add tor.
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/ https://www.openbsd.org/faq/index.html
For FreeBSD, you’ll want to switch packages from quarterly to latest prior to installing tor though.
/etc/pkg/FreeBSD.conf: url: "pkg+https://pkg.FreeBSD.org/$%7BABI%7D/latest",
You may also compile from source - the ports collection is available on each instance.
If not using ports, only the libevent and tor tarballs from their sites are needed, they work fine.