A kernel called eXcaliBur based off of the CyanogenMod-based LiquidSmooth kernel with a bunch of extras has been released for those running AOSP ROMs on the HTC One M8.
It ships with the Motorola Memutils, Kernel Mode NEON, Linaro power efficient work queues, fast LCD, lowered vibration, fast charge, fsync, Flar2’s wake gestures, faux sound control, overclock/undervolt, and all the IO governors one could ask for. It also ships with CPUQuiet and Input Mediator from Maxwen, which supposedly is better for battery and smoothness than Qualcomm/HTC stock settings, but it’s probably up for debate.
Beyond the rich feature set, the standard warnings apply: AOSP only (if you don’t know if you’re on AOSP you’re probably no); make a nandroid backup or have a good flashable kernel laying around in case of lockups or strangeness; and beware strange farm animals that ask if they can make a call using your phone.
The kernel’s only been out a couple of days, so there’s not a lot of reports about what it does and does not work on in the development thread. If it works or doesn’t for your ROM, drop us a note here.