Today CyanogenMod announced Marshmallow based CM 13 Nightly builds for HTC One A9 and MOTO E (1st gen). It’s available for GSM model only.
MOTO E (1st gen) is not getting Android 6.0 officially, so if you want to get a taste of Android 6.0 then you can download CM 13 Nightly builds and enjoy Marshmallow.
HTC One A9 has Android 6.0 officially available for it, but if you want to get close to the CM 13 then download builds. Also you need to be aware that these CM builds may not be not stable, probably void your warranty. You can download from here: