Update April 14: Nexus 7 (2013) WiFi and LTE models, along with the Nexus 4 are now available.

Update April 8: Google added Android 5.1 (LMY47D) images for the Nexus 7 2012 “Mobile.”

Updated March 25: Google added Android 5.1 (LMY47I) images for the Nexus 5 and Nexus 6.

Updated March 20: Google added the Android 5.1 (LMY47D) image for the Nexus Player.

Updated March 17: Google just added a new Android 5.1 factory image for the Nexus 6 as build LMY47E.

Updated March 12: Nexus 6 factory images added.

The first batch of Android 5.1 factory images are now available for the Nexus 5, Nexus 10, and Nexus 7 (2012).

You will find links to all below. We will update this post as we have more.

Factory Images (Android 5.1):

Instructions for flashing factory images can be found here.