The CyanogenMod team continues to expand its selection of builds for its aftermarket ROM, and today no less than four new devices are being added. Those would be HTC's 2015 flagship One M9, Lenovo's budget-oriented ZUK Z1, NVIDIA's SHIELD Portable (the original one with the attached controller), and the SHIELD Tablet.
As usual, CyanogenMod arranges builds by codename: the M9 is "himaul," the Z1 is "ham," the SHIELD Portable is "roth," and the SHIELD Tablet is... "shieldtablet." Huh. All four devices are currently on nightly builds of CyanogenMod 12.1 (Android 5.1), and may or may not be added to the more stable releases as they come. The CM team doesn't "graduate" phones or tablets to more stable designations until they've passed certain usability and stability requirements. Keep in mind that the One M9 build probably only works for the international version.
AOSP-based ROMs for the One M9 and ZUK Z1 are desirable if only for an alternative to manufacturer skins, but as an owner of both the SHIELD Portable and Tablet, I'd hold off on them. NVIDIA updates its first-party software frequently, and both of them are running fairly "clean" versions of Android 5.1 anyway. Still, if you'd prefer to tinker, go ahead and flash away.