OpenBSD has begun forming builds for the powerpc64 architecture.

OpenBSD developers organized publication snapshots for systems based on POWER9. If developers do not lose interest, powerpc64 will become the thirteenth officially supported hardware platform in OpenBSD, not counting 20 obsolete platforms, support for which has been discontinued. Currently, the list of officially supported architectures in OpenBSD includes:
alpha, amd64, arm64, armv7, hppa, i386, landisk, loongson, luna88k, macppc, octeon, and sparc64.

Source: opennet.ru