Is still fun! There is Tumbleweed, a full rolling distribution (all packages with its own update cadence, and OBS fully building the dependencies that are impacted). There is also MicroOS, a transactional OS (BtrFS subvolumes for rootfs are read-only, and the update happens in the snapshot that will be activated after the reboot, providing a self-healing system when an upgrade does not affect the running environment)
Also Leap, but this is indeed boring (15.3 will be based fully in SLE binaries)