There has already been one spin-off, Angel, but that has stayed on the WB network.

BBC: Bosses signal 'end of Buffy'

Or painfully obvious:For Pepsi Smash, a summer concert series on the WB network, the cola company helped design the set and pick the hosts.

FORBES: Magazine Article

While running the now-defunct WB network, which he left in 2004, he commissioned a show called Global Frequency, a sci-fi adventure about a secretive global organization.

FORBES: Magazine Article