Vhyle
Jackson Shill
What are some black metal bands with odd time signatures?
This might not quite be what you're looking for, but the opening riffs and chorus are in 5/4. This particular track isn't as fast-paced as typical black metal, but Mork Gryning was very much a black metal band.
This one is a 3/4 waltz, essentially. Does that count? Regardless, this album is incredible.
The intro riffs on this track could be counted in a 9/8 swing beat, if that makes sense.
Or, you could listen to Emperor's Prometheus album. It has a few odd-time moments here and there.
But your question brings up a good point - there isn't honestly many black metal bands that explore really odd time signatures. But once you start delving into the more jazz-oriented or experimental bands, it becomes a bit more common.