Most others will have to wait for the software to be integrated by a handset maker and then tested by a carrier before getting Android 6.0 pushed to phones.
Here's a list of what we know so far. We'll update it as more information becomes available.
Nexus 5, Nexus 6, Nexus 7 from 2013, Nexus 9, and Nexus Player
2015 Moto X Pure Edition (3rd gen), 2015 Moto X Style (3rd gen), 2015 Moto X Play, 2015 Moto G (3rd gen), 2014 Moto X Pure Edition in the US (2nd gen), 2014 Moto X in Latin America, Europe and Asia2 (2nd gen), 2014 Moto G and Moto G with 4G LTE2 (2nd gen), DROID Turbo, 2014 Moto MAXX, 2014 Moto Turbo, Nexus 6 (Google's 2014 handset built by Motorola)
When should you expect your listed device to get the software update?
Again, if you went (or plan to go) with a Google Nexus, you're going to be among the first to see Android 6.0 Marshmallow. After that, it's really up in the air but phones from Motorola and HTC are most likely to lead the way; HTC has a 90-day target for software updates even if it won't commit to monthly Android security updates.
Everyone else will probably follow over the next three to six months based on the efforts of handset makers and carrier testing.