Just by looking at Fluxbox, one can see the resemblance it bears to Blackbox 0.61.1. That's because Fluxbox handles styles, colors, window placement and similar things exactly like Blackbox.
Fluxbox has 100% theme and style compatibility with Blackbox. Fluxbox looks like Blackbox.
This is the place where you get get the latest spiffy Fluxbox themes as well as the ones that are shipped in the tarball (if you somehow lost or removed them).
What's more, Fluxbox won the 2003 LinuxQuestions.org Members Choice Award for the Best Window Manager.