The BSD Projects
FreeBSD: The flagship BSD project with solid academic roots.
DragonFly BSD: Originally a fork of FreeBSD, DragonFly BSD is now a superb BSD with many unique features.
NetBSD: Of the BSD projects, by far the most portable.
OpenBSD: OpenBSD focuses on proactive security and code correctness.
TrueOS: Now specifically focused on servers. Sponsored by iXsystems.
HardendedBSD supporting multiple additional security features on top of stock FreeBSD.
Desktops of Note
GhostBSD: An elegant desktop BSD based on stock FreeBSD. Supports MATE and other desktop managers.
MidnightBSD: Billed as “the BSD for everyone”, MidnightBSD supports common applications out of the box.
Fury BSD: A BSD desktop based on stock FreeBSD, featuring XFCE and other desktops. Under active development.
Project Trident: A former BSD desktop has migrated over to Void Linux, while keeping the same look and feel, as well as application support, ZFS, and other features.