Fray is good - all new characters, but still very much Joss. There's an Angel series from IDW (I think?), and um...hide. It is cringeworthy. I tried one issue, haven't gone back.

There is a one-shot, Spike vs. Dracula by Peter David, which sounds like a recipe for awesome...but isn't. I didn't like it, although I at least know people who do.

There are a handful of Tales of the Slayers and Tales of the Vampires - he wrote some, and was somehow involved with the rest and it definitely shows. I highly recommend those. (I think both are available in trades as well.)

Also, when reading Buffy issue 3, I'm pretty sure I noticed someone reading Fray. (And possibly the face of Joss in one of the dream sequences.)