If it were not for Debian creating their kFreeBSD version of their distribution, FreeBSD would not have the capability of having Debian in their mediocre jails to boast about.
The Gentoo community tries very hard to make their distribution as BSD like as possible. Thus allowing FreeBSD to have Gentoo in their jails until 2012 when misguided changes in the FreeBSD kernel made that impossible.
With the ArchBSD project created by a person named Amzo, BSD which soon be able too have Arch jails too. But Amzo has been treated like excrement by BSD supporters when discussing about it.
Developed and implemented on GCC and is not heavily used on OpenBSD. In fact, all security features on OpenBSD were actually pioneered on GNU/Linux.
FreeBSD’s PKGNG and NetBSD’s PKGIN:
These are all illegal strip down forks of Debian’s APT-GET.
A stripped down copy of IPTABLES.
Stolen from a Linux prototype.
Ports and pkgsrc:
The ideal was pioneered by GNU’s Stallman when he demanded that the source code of a program be made avalible as well.
Intel and AMD KMS
Linux developers licensed their KMS components under the MIT license rather then the GPL (a mistake in my view). This allowed FreeBSD and OpenBSD developers to port KMS over legally. If the drivers were GPLed, they have to be done illegally.
There are many more but I don’t have time to list them know.