Berkeley DB brought durable key-value storage, concurrency, and transactions into a library linked directly with applications, proving that a database did not need to be a separate server.
FreeBSD emerged from the 386BSD patch community, rebuilt on 4.4BSD-Lite after the Unix legal settlement, and preserved Berkeley Unix as a complete collaboratively engineered operating system.
Mac OS X replaced the classic Mac OS core with a Darwin foundation built from Mach, BSD and NeXT technology while preserving Macintosh interface conventions through Cocoa, Carbon and compatibility layers.
The FreeBSD Ports Collection separated software recipes from upstream source code, letting a shared tree of Makefiles, patches and metadata automate fetching, configuring, compiling and packaging third-party applications.
The BSD licensing tradition allowed source and binary redistribution with minimal conditions, creating a model in which open code could move freely into academic, open-source and proprietary systems alike.